From d2e768d0d0709a37db0952d721cad20a1dfd9c4a Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 20 Dec 2020 20:46:29 +0100
Subject: [PATCH 01/31] Document CC constructors

---
 telegram/ext/callbackcontext.py | 88 ++++++++++++++++++++++++++++-----
 1 file changed, 75 insertions(+), 13 deletions(-)

diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
index 20ea6fb8812..008e20f77f4 100644
--- a/telegram/ext/callbackcontext.py
+++ b/telegram/ext/callbackcontext.py
@@ -50,20 +50,10 @@ class CallbackContext:
          almost certainly execute the callbacks for an update out of order, and the attributes
          that you think you added will not be present.
 
-    Attributes:
-        bot_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
-            update it will be the same ``dict``.
-        chat_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
-            update from the same chat id it will be the same ``dict``.
-
-            Warning:
-                When a group chat migrates to a supergroup, its chat id will change and the
-                ``chat_data`` needs to be transferred. For details see our `wiki page
-                <https://github.com/python-telegram-bot/python-telegram-bot/wiki/
-                Storing-user--and-chat-related-data#chat-migration>`_.
+    Args:
+        dispatcher (:class:`telegram.ext.Dispatcher`): The dispatcher associated with this context.
 
-        user_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
-            update from the same user it will be the same ``dict``.
+    Attributes:
         matches (List[:obj:`re match object`]): Optional. If the associated update originated from
             a regex-supported handler or had a :class:`Filters.regex`, this will contain a list of
             match objects for every pattern where ``re.search(pattern, string)`` returned a match.
@@ -114,6 +104,10 @@ def dispatcher(self) -> 'Dispatcher':
 
     @property
     def bot_data(self) -> Dict:
+        """
+        bot_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
+            update it will be the same :obj:`dict`.
+        """
         return self._bot_data
 
     @bot_data.setter
@@ -124,6 +118,17 @@ def bot_data(self, value: Any) -> NoReturn:
 
     @property
     def chat_data(self) -> Optional[Dict]:
+        """
+
+        chat_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
+            update from the same chat id it will be the same :obj:`dict`.
+
+            Warning:
+                When a group chat migrates to a supergroup, its chat id will change and the
+                ``chat_data`` needs to be transferred. For details see our `wiki page
+                <https://github.com/python-telegram-bot/python-telegram-bot/wiki/
+                Storing-user--and-chat-related-data#chat-migration>`_.
+        """
         return self._chat_data
 
     @chat_data.setter
@@ -134,6 +139,10 @@ def chat_data(self, value: Any) -> NoReturn:
 
     @property
     def user_data(self) -> Optional[Dict]:
+        """
+        user_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
+            update from the same user it will be the same :obj:`dict`.
+        """
         return self._user_data
 
     @user_data.setter
@@ -151,6 +160,29 @@ def from_error(
         async_args: Union[List, Tuple] = None,
         async_kwargs: Dict[str, Any] = None,
     ) -> 'CallbackContext':
+        """
+        Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to the error
+        handlers.
+
+        .. seealso:: :meth:`telegram.ext.Dispatcher.add_error_handler`
+
+        Args:
+            update (:obj:`any` | :class:`telegram.Update`): The update associated with the error.
+                May be :obj:`None`, e.g. for errors in job callbacks.
+            error (:obj:`Exception`): The error.
+            dispatcher (:class:`telegram.ext.Dispatcher`): The dispatcher associated with this
+                context.
+            async_args (List[:obj:`object`]): Optional. Positional arguments of the function that
+                raised the error. Pass only when the raising function was run asynchronously using
+                :meth:`telegram.ext.Dispatcher.run_async`.
+            async_kwargs (Dict[:obj:`str`, :obj:`object`]): Optional. Keyword arguments of the
+                function that raised the error. Pass only when the raising function was run
+                asynchronously using :meth:`telegram.ext.Dispatcher.run_async`.
+
+        Returns:
+            :class:`telegram.ext.CallbackContext`
+
+        """
         self = cls.from_update(update, dispatcher)
         self.error = error
         self.async_args = async_args
@@ -159,6 +191,21 @@ def from_error(
 
     @classmethod
     def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CallbackContext':
+        """
+        Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to the
+        handlers.
+
+        .. seealso:: :meth:`telegram.ext.Dispatcher.add_handler`
+
+        Args:
+            update (:obj:`any` | :class:`telegram.Update`): The update.
+            dispatcher (:class:`telegram.ext.Dispatcher`): The dispatcher associated with this
+                context.
+
+        Returns:
+            :class:`telegram.ext.CallbackContext`
+
+        """
         self = cls(dispatcher)
 
         if update is not None and isinstance(update, Update):
@@ -173,6 +220,21 @@ def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CallbackConte
 
     @classmethod
     def from_job(cls, job: 'Job', dispatcher: 'Dispatcher') -> 'CallbackContext':
+        """
+        Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to a
+        job callback.
+
+        .. seealso:: :meth:`telegram.ext.JobQueue`
+
+        Args:
+            job (:class:`telegram.ext.Job`): The job.
+            dispatcher (:class:`telegram.ext.Dispatcher`): The dispatcher associated with this
+                context.
+
+        Returns:
+            :class:`telegram.ext.CallbackContext`
+
+        """
         self = cls(dispatcher)
         self.job = job
         return self

From 4f8014f1b11941658e2d5b6a97b5ffb61cb11647 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Tue, 22 Dec 2020 13:34:43 +0100
Subject: [PATCH 02/31] Add custom_context parameter and try to sort out
 annotations

---
 examples/echobot.py                       |  2 +-
 telegram/ext/callbackqueryhandler.py      |  9 ++-
 telegram/ext/choseninlineresulthandler.py |  3 +-
 telegram/ext/commandhandler.py            | 14 ++--
 telegram/ext/conversationhandler.py       | 10 +--
 telegram/ext/dispatcher.py                | 95 ++++++++++++++++++++---
 telegram/ext/handler.py                   | 11 +--
 telegram/ext/inlinequeryhandler.py        |  9 ++-
 telegram/ext/jobqueue.py                  |  4 +-
 telegram/ext/messagehandler.py            |  9 ++-
 telegram/ext/pollanswerhandler.py         |  3 +-
 telegram/ext/pollhandler.py               |  3 +-
 telegram/ext/precheckoutqueryhandler.py   |  3 +-
 telegram/ext/regexhandler.py              |  5 +-
 telegram/ext/shippingqueryhandler.py      |  3 +-
 telegram/ext/stringcommandhandler.py      |  9 ++-
 telegram/ext/stringregexhandler.py        |  9 ++-
 telegram/ext/typehandler.py               | 10 +--
 telegram/ext/updater.py                   | 30 ++++++-
 telegram/utils/types.py                   |  4 +
 20 files changed, 176 insertions(+), 69 deletions(-)

diff --git a/examples/echobot.py b/examples/echobot.py
index c8a264584bd..bb9ceb855bd 100644
--- a/examples/echobot.py
+++ b/examples/echobot.py
@@ -42,7 +42,7 @@ def help_command(update: Update, context: CallbackContext) -> None:
     update.message.reply_text('Help!')
 
 
-def echo(update: Update, context: CallbackContext) -> None:
+def echo(update: str, context: CallbackContext) -> None:
     """Echo the user message."""
     update.message.reply_text(update.message.text)
 
diff --git a/telegram/ext/callbackqueryhandler.py b/telegram/ext/callbackqueryhandler.py
index c229de76a2a..9c13f17ed06 100644
--- a/telegram/ext/callbackqueryhandler.py
+++ b/telegram/ext/callbackqueryhandler.py
@@ -36,14 +36,15 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
+from ..utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class CallbackQueryHandler(Handler[Update]):
+class CallbackQueryHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram callback queries. Optionally based on a regex.
 
     Read the documentation of the ``re`` module for more information.
@@ -122,7 +123,7 @@ class CallbackQueryHandler(Handler[Update]):
 
     def __init__(
         self,
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
         pattern: Union[str, Pattern] = None,
@@ -185,7 +186,7 @@ def collect_optional_args(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: Update,
         dispatcher: 'Dispatcher',
         check_result: Union[bool, Match],
diff --git a/telegram/ext/choseninlineresulthandler.py b/telegram/ext/choseninlineresulthandler.py
index f65cb2e97b4..ff50c34974a 100644
--- a/telegram/ext/choseninlineresulthandler.py
+++ b/telegram/ext/choseninlineresulthandler.py
@@ -23,11 +23,12 @@
 from telegram import Update
 
 from .handler import Handler
+from ..utils.types import CCT
 
 RT = TypeVar('RT')
 
 
-class ChosenInlineResultHandler(Handler[Update]):
+class ChosenInlineResultHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram updates that contain a chosen inline result.
 
     Attributes:
diff --git a/telegram/ext/commandhandler.py b/telegram/ext/commandhandler.py
index 41a3d490702..bf1f4a07c8d 100644
--- a/telegram/ext/commandhandler.py
+++ b/telegram/ext/commandhandler.py
@@ -24,18 +24,18 @@
 from telegram import MessageEntity, Update
 from telegram.ext import BaseFilter, Filters
 from telegram.utils.deprecate import TelegramDeprecationWarning
-from telegram.utils.types import SLT
+from telegram.utils.types import SLT, CCT
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class CommandHandler(Handler[Update]):
+class CommandHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram commands.
 
     Commands are Telegram messages that start with ``/``, optionally followed by an ``@`` and the
@@ -134,7 +134,7 @@ class CommandHandler(Handler[Update]):
     def __init__(
         self,
         command: SLT[str],
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         filters: BaseFilter = None,
         allow_edited: bool = None,
         pass_args: bool = False,
@@ -228,7 +228,7 @@ def collect_optional_args(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: Update,
         dispatcher: 'Dispatcher',
         check_result: Optional[Union[bool, Tuple[List[str], Optional[bool]]]],
@@ -344,7 +344,7 @@ def __init__(
         self,
         prefix: SLT[str],
         command: SLT[str],
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         filters: BaseFilter = None,
         pass_args: bool = False,
         pass_update_queue: bool = False,
@@ -441,7 +441,7 @@ def check_update(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: Update,
         dispatcher: 'Dispatcher',
         check_result: Optional[Union[bool, Tuple[List[str], Optional[bool]]]],
diff --git a/telegram/ext/conversationhandler.py b/telegram/ext/conversationhandler.py
index 8de9e58ec60..9e246de5479 100644
--- a/telegram/ext/conversationhandler.py
+++ b/telegram/ext/conversationhandler.py
@@ -35,7 +35,7 @@
     InlineQueryHandler,
 )
 from telegram.utils.promise import Promise
-from telegram.utils.types import ConversationDict
+from telegram.utils.types import ConversationDict, CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher, Job
@@ -56,7 +56,7 @@ def __init__(
         self.callback_context = callback_context
 
 
-class ConversationHandler(Handler[Update]):
+class ConversationHandler(Handler[Update, CCT]):
     """
     A handler to hold a conversation with a single user by managing four collections of other
     handlers.
@@ -181,9 +181,9 @@ class ConversationHandler(Handler[Update]):
     # pylint: disable=W0231
     def __init__(
         self,
-        entry_points: List[Handler],
-        states: Dict[object, List[Handler]],
-        fallbacks: List[Handler],
+        entry_points: List[Handler[Update, CCT]],
+        states: Dict[object, List[Handler[Update, CCT]]],
+        fallbacks: List[Handler[Update, CCT]],
         allow_reentry: bool = False,
         per_chat: bool = True,
         per_user: bool = True,
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index acee97c657e..76a7193bfb2 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -26,7 +26,21 @@
 from queue import Empty, Queue
 from threading import BoundedSemaphore, Event, Lock, Thread, current_thread
 from time import sleep
-from typing import TYPE_CHECKING, Any, Callable, DefaultDict, Dict, List, Optional, Set, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    DefaultDict,
+    Dict,
+    List,
+    Optional,
+    Set,
+    Union,
+    Generic,
+    Type,
+    TypeVar,
+    overload,
+)
 from uuid import uuid4
 
 from telegram import TelegramError, Update
@@ -36,6 +50,8 @@
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
+from telegram.utils.types import CCT
+
 
 if TYPE_CHECKING:
     from telegram import Bot
@@ -43,6 +59,8 @@
 
 DEFAULT_GROUP: int = 0
 
+UT = TypeVar('UT')
+
 
 def run_async(
     func: Callable[[Update, CallbackContext], Any]
@@ -103,7 +121,7 @@ def __init__(self, state: object = None) -> None:
         self.state = state
 
 
-class Dispatcher:
+class Dispatcher(Generic[CCT]):
     """This class dispatches all kinds of updates to its registered handlers.
 
     Attributes:
@@ -118,6 +136,8 @@ class Dispatcher:
         bot_data (:obj:`dict`): A dictionary handlers can use to store data for the bot.
         persistence (:class:`telegram.ext.BasePersistence`): Optional. The persistence class to
             store data that should be persistent over restarts.
+        context_class (:obj:`class`): The class to use for the ``context`` argument of the
+            callbacks.
 
     Args:
         bot (:class:`telegram.Bot`): The bot object that should be passed to the handlers.
@@ -131,6 +151,11 @@ class Dispatcher:
         use_context (:obj:`bool`, optional): If set to :obj:`True` uses the context based callback
             API (ignored if `dispatcher` argument is used). Defaults to :obj:`True`.
             **New users**: set this to :obj:`True`.
+        custom_context (:obj:`class`, optional): Pass a subclass of
+            :class:`telegram.ext.CallbackContext` to be used instead of
+            :class:`telegram.ext.CallbackContext`, i.e. the ``context`` argument in all the
+            callbacks will be of this type instead. Defaults to
+            :class:`telegram.ext.CallbackContext`.
 
     """
 
@@ -139,6 +164,33 @@ class Dispatcher:
     __singleton = None
     logger = logging.getLogger(__name__)
 
+    @overload
+    def __init__(
+        self: 'Dispatcher'['CallbackContext'],  # pylint: disable=E1126
+        bot: 'Bot',
+        update_queue: Queue,
+        workers: int = 4,
+        exception_event: Event = None,
+        job_queue: 'JobQueue' = None,
+        persistence: BasePersistence = None,
+        use_context: bool = True,
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'Dispatcher'[CCT],  # pylint: disable=E1126
+        bot: 'Bot',
+        update_queue: Queue,
+        workers: int = 4,
+        exception_event: Event = None,
+        job_queue: 'JobQueue' = None,
+        persistence: BasePersistence = None,
+        use_context: bool = True,
+        custom_context: Type[CCT] = None,
+    ):
+        ...
+
     def __init__(
         self,
         bot: 'Bot',
@@ -148,6 +200,7 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
+        custom_context: Type[CCT] = None,
     ):
         self.bot = bot
         self.update_queue = update_queue
@@ -161,6 +214,16 @@ def __init__(
                 TelegramDeprecationWarning,
                 stacklevel=3,
             )
+        if not use_context and custom_context:
+            raise ValueError(
+                'Custom CallbackContext classes can only be used, when use_context=True.'
+            )
+        if custom_context:
+            if not issubclass(custom_context, CallbackContext):
+                raise ValueError('custom_context must be a subclass of CallbackContext')
+            self.context_class = custom_context
+        else:
+            self.context_class = CallbackContext  # type: ignore[assignment]
 
         self.user_data: DefaultDict[int, Dict[Any, Any]] = defaultdict(dict)
         self.chat_data: DefaultDict[int, Dict[Any, Any]] = defaultdict(dict)
@@ -427,7 +490,7 @@ def process_update(self, update: Union[str, Update, TelegramError]) -> None:
                     check = handler.check_update(update)
                     if check is not None and check is not False:
                         if not context and self.use_context:
-                            context = CallbackContext.from_update(update, self)
+                            context = self.context_class.from_update(update, self)
                         handler.handle_update(update, self, check, context)
 
                         # If handler runs async updating immediately doesn't make sense
@@ -452,7 +515,7 @@ def process_update(self, update: Union[str, Update, TelegramError]) -> None:
                 except Exception:
                     self.logger.exception('An uncaught error was raised while handling the error.')
 
-    def add_handler(self, handler: Handler, group: int = DEFAULT_GROUP) -> None:
+    def add_handler(self, handler: Handler[UT, CCT], group: int = DEFAULT_GROUP) -> None:
         """Register a handler.
 
         TL;DR: Order and priority counts. 0 or 1 handlers per group will be used. End handling of
@@ -484,14 +547,22 @@ def add_handler(self, handler: Handler, group: int = DEFAULT_GROUP) -> None:
             raise TypeError(f'handler is not an instance of {Handler.__name__}')
         if not isinstance(group, int):
             raise TypeError('group is not int')
-        if isinstance(handler, ConversationHandler) and handler.persistent and handler.name:
+        # For some reason MyPy infers the type of handler is <nothing> here,
+        # so for now we just ignore all the errors
+        if (
+            isinstance(handler, ConversationHandler)
+            and handler.persistent  # type: ignore[attr-defined]
+            and handler.name  # type: ignore[attr-defined]
+        ):
             if not self.persistence:
                 raise ValueError(
-                    f"ConversationHandler {handler.name} can not be persistent if dispatcher has "
-                    f"no persistence"
+                    f"ConversationHandler {handler.name} "  # type: ignore[attr-defined]
+                    f"can not be persistent if dispatcher has no persistence"
                 )
-            handler.persistence = self.persistence
-            handler.conversations = self.persistence.get_conversations(handler.name)
+            handler.persistence = self.persistence  # type: ignore[attr-defined]
+            handler.conversations = (  # type: ignore[attr-defined]
+                self.persistence.get_conversations(handler.name)  # type: ignore[attr-defined]
+            )
 
         if group not in self.handlers:
             self.handlers[group] = list()
@@ -585,7 +656,7 @@ def __update_persistence(self, update: Any = None) -> None:
 
     def add_error_handler(
         self,
-        callback: Callable[[Any, CallbackContext], None],
+        callback: Callable[[Any, CCT], None],
         run_async: Union[bool, DefaultValue] = DEFAULT_FALSE,  # pylint: disable=W0621
     ) -> None:
         """Registers an error handler in the Dispatcher. This handler will receive every error
@@ -621,7 +692,7 @@ def add_error_handler(
 
         self.error_handlers[callback] = run_async
 
-    def remove_error_handler(self, callback: Callable[[Any, CallbackContext], None]) -> None:
+    def remove_error_handler(self, callback: Callable[[Any, CCT], None]) -> None:
         """Removes an error handler.
 
         Args:
@@ -648,7 +719,7 @@ def dispatch_error(
         if self.error_handlers:
             for callback, run_async in self.error_handlers.items():  # pylint: disable=W0621
                 if self.use_context:
-                    context = CallbackContext.from_error(
+                    context = self.context_class.from_error(
                         update, error, self, async_args=async_args, async_kwargs=async_kwargs
                     )
                     if run_async:
diff --git a/telegram/ext/handler.py b/telegram/ext/handler.py
index 123ba543e0b..b0342121214 100644
--- a/telegram/ext/handler.py
+++ b/telegram/ext/handler.py
@@ -24,15 +24,16 @@
 from telegram import Update
 from telegram.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
+from telegram.utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 UT = TypeVar('UT')
 
 
-class Handler(Generic[UT], ABC):
+class Handler(Generic[UT, CCT], ABC):
     """The base class for all update handlers. Create custom handlers by inheriting from it.
 
     Attributes:
@@ -92,7 +93,7 @@ class Handler(Generic[UT], ABC):
 
     def __init__(
         self,
-        callback: Callable[[UT, 'CallbackContext'], RT],
+        callback: Callable[[UT, CCT], RT],
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
         pass_user_data: bool = False,
@@ -131,7 +132,7 @@ def handle_update(
         update: UT,
         dispatcher: 'Dispatcher',
         check_result: object,
-        context: 'CallbackContext' = None,
+        context: CCT = None,
     ) -> Union[RT, Promise]:
         """
         This method is called if it was determined that an update should indeed
@@ -168,7 +169,7 @@ def handle_update(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: UT,
         dispatcher: 'Dispatcher',
         check_result: Any,
diff --git a/telegram/ext/inlinequeryhandler.py b/telegram/ext/inlinequeryhandler.py
index 4e30ca9910f..4420af07ff2 100644
--- a/telegram/ext/inlinequeryhandler.py
+++ b/telegram/ext/inlinequeryhandler.py
@@ -35,14 +35,15 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
+from ..utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class InlineQueryHandler(Handler[Update]):
+class InlineQueryHandler(Handler[Update, CCT]):
     """
     Handler class to handle Telegram inline queries. Optionally based on a regex. Read the
     documentation of the ``re`` module for more information.
@@ -121,7 +122,7 @@ class InlineQueryHandler(Handler[Update]):
 
     def __init__(
         self,
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
         pattern: Union[str, Pattern] = None,
@@ -186,7 +187,7 @@ def collect_optional_args(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: Update,
         dispatcher: 'Dispatcher',
         check_result: Optional[Union[bool, Match]],
diff --git a/telegram/ext/jobqueue.py b/telegram/ext/jobqueue.py
index c176eaf25f4..8c391570884 100644
--- a/telegram/ext/jobqueue.py
+++ b/telegram/ext/jobqueue.py
@@ -70,7 +70,7 @@ def aps_log_filter(record):  # type: ignore
 
     def _build_args(self, job: 'Job') -> List[Union[CallbackContext, 'Bot', 'Job']]:
         if self._dispatcher.use_context:
-            return [CallbackContext.from_job(job, self._dispatcher)]
+            return [self._dispatcher.context_class.from_job(job, self._dispatcher)]
         return [self._dispatcher.bot, job]
 
     def _tz_now(self) -> datetime.datetime:
@@ -568,7 +568,7 @@ def run(self, dispatcher: 'Dispatcher') -> None:
         """Executes the callback function independently of the jobs schedule."""
         try:
             if dispatcher.use_context:
-                self.callback(CallbackContext.from_job(self, dispatcher))
+                self.callback(dispatcher.context_class.from_job(self, dispatcher))
             else:
                 self.callback(dispatcher.bot, self)  # type: ignore[arg-type,call-arg]
         except Exception as exc:
diff --git a/telegram/ext/messagehandler.py b/telegram/ext/messagehandler.py
index 10b05d0bf57..71450821aef 100644
--- a/telegram/ext/messagehandler.py
+++ b/telegram/ext/messagehandler.py
@@ -27,14 +27,15 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
+from ..utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class MessageHandler(Handler[Update]):
+class MessageHandler(Handler[Update, CCT]):
     """Handler class to handle telegram messages. They might contain text, media or status updates.
 
     Attributes:
@@ -123,7 +124,7 @@ class MessageHandler(Handler[Update]):
     def __init__(
         self,
         filters: BaseFilter,
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
         pass_user_data: bool = False,
@@ -195,7 +196,7 @@ def check_update(self, update: Any) -> Optional[Union[bool, Dict[str, Any]]]:
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: Update,
         dispatcher: 'Dispatcher',
         check_result: Optional[Union[bool, Dict[str, Any]]],
diff --git a/telegram/ext/pollanswerhandler.py b/telegram/ext/pollanswerhandler.py
index 17fd00ff00e..72ca7c40506 100644
--- a/telegram/ext/pollanswerhandler.py
+++ b/telegram/ext/pollanswerhandler.py
@@ -22,9 +22,10 @@
 from telegram import Update
 
 from .handler import Handler
+from ..utils.types import CCT
 
 
-class PollAnswerHandler(Handler[Update]):
+class PollAnswerHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram updates that contain a poll answer.
 
     Attributes:
diff --git a/telegram/ext/pollhandler.py b/telegram/ext/pollhandler.py
index 02f71edaeee..69f8f393fe9 100644
--- a/telegram/ext/pollhandler.py
+++ b/telegram/ext/pollhandler.py
@@ -22,9 +22,10 @@
 from telegram import Update
 
 from .handler import Handler
+from ..utils.types import CCT
 
 
-class PollHandler(Handler[Update]):
+class PollHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram updates that contain a poll.
 
     Attributes:
diff --git a/telegram/ext/precheckoutqueryhandler.py b/telegram/ext/precheckoutqueryhandler.py
index 332279d18c0..bd6c172861d 100644
--- a/telegram/ext/precheckoutqueryhandler.py
+++ b/telegram/ext/precheckoutqueryhandler.py
@@ -22,9 +22,10 @@
 from telegram import Update
 
 from .handler import Handler
+from ..utils.types import CCT
 
 
-class PreCheckoutQueryHandler(Handler[Update]):
+class PreCheckoutQueryHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram PreCheckout callback queries.
 
     Attributes:
diff --git a/telegram/ext/regexhandler.py b/telegram/ext/regexhandler.py
index ab6432843de..3ce4b165737 100644
--- a/telegram/ext/regexhandler.py
+++ b/telegram/ext/regexhandler.py
@@ -26,9 +26,10 @@
 from telegram.ext import Filters, MessageHandler
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
+from telegram.utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
@@ -111,7 +112,7 @@ class RegexHandler(MessageHandler):
     def __init__(
         self,
         pattern: Union[str, Pattern],
-        callback: Callable[[Update, 'CallbackContext'], RT],
+        callback: Callable[[Update, CCT], RT],
         pass_groups: bool = False,
         pass_groupdict: bool = False,
         pass_update_queue: bool = False,
diff --git a/telegram/ext/shippingqueryhandler.py b/telegram/ext/shippingqueryhandler.py
index d5a5d372538..d82aafe28e3 100644
--- a/telegram/ext/shippingqueryhandler.py
+++ b/telegram/ext/shippingqueryhandler.py
@@ -21,9 +21,10 @@
 
 from telegram import Update
 from .handler import Handler
+from ..utils.types import CCT
 
 
-class ShippingQueryHandler(Handler[Update]):
+class ShippingQueryHandler(Handler[Update, CCT]):
     """Handler class to handle Telegram shipping callback queries.
 
     Attributes:
diff --git a/telegram/ext/stringcommandhandler.py b/telegram/ext/stringcommandhandler.py
index 068cbb7b2b4..80179d16c25 100644
--- a/telegram/ext/stringcommandhandler.py
+++ b/telegram/ext/stringcommandhandler.py
@@ -23,14 +23,15 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
+from ..utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class StringCommandHandler(Handler[str]):
+class StringCommandHandler(Handler[str, CCT]):
     """Handler class to handle string commands. Commands are string updates that start with ``/``.
 
     Note:
@@ -85,7 +86,7 @@ class StringCommandHandler(Handler[str]):
     def __init__(
         self,
         command: str,
-        callback: Callable[[str, 'CallbackContext'], RT],
+        callback: Callable[[str, CCT], RT],
         pass_args: bool = False,
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
@@ -129,7 +130,7 @@ def collect_optional_args(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: str,
         dispatcher: 'Dispatcher',
         check_result: Optional[List[str]],
diff --git a/telegram/ext/stringregexhandler.py b/telegram/ext/stringregexhandler.py
index 6caac3d3861..d40ccd3f104 100644
--- a/telegram/ext/stringregexhandler.py
+++ b/telegram/ext/stringregexhandler.py
@@ -24,14 +24,15 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
+from ..utils.types import CCT
 
 if TYPE_CHECKING:
-    from telegram.ext import CallbackContext, Dispatcher
+    from telegram.ext import Dispatcher
 
 RT = TypeVar('RT')
 
 
-class StringRegexHandler(Handler[str]):
+class StringRegexHandler(Handler[str, CCT]):
     """Handler class to handle string updates based on a regex which checks the update content.
 
     Read the documentation of the ``re`` module for more information. The ``re.match`` function is
@@ -94,7 +95,7 @@ class StringRegexHandler(Handler[str]):
     def __init__(
         self,
         pattern: Union[str, Pattern],
-        callback: Callable[[str, 'CallbackContext'], RT],
+        callback: Callable[[str, CCT], RT],
         pass_groups: bool = False,
         pass_groupdict: bool = False,
         pass_update_queue: bool = False,
@@ -147,7 +148,7 @@ def collect_optional_args(
 
     def collect_additional_context(
         self,
-        context: 'CallbackContext',
+        context: CCT,
         update: str,
         dispatcher: 'Dispatcher',
         check_result: Optional[Match],
diff --git a/telegram/ext/typehandler.py b/telegram/ext/typehandler.py
index 7d40a0b5b47..1e3d1bc718b 100644
--- a/telegram/ext/typehandler.py
+++ b/telegram/ext/typehandler.py
@@ -18,19 +18,17 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains the TypeHandler class."""
 
-from typing import TYPE_CHECKING, Any, Callable, Type, TypeVar, Union
+from typing import Any, Callable, Type, TypeVar, Union
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-
-if TYPE_CHECKING:
-    from telegram.ext import CallbackContext
+from ..utils.types import CCT
 
 RT = TypeVar('RT')
 UT = TypeVar('UT')
 
 
-class TypeHandler(Handler[UT]):
+class TypeHandler(Handler[UT, CCT]):
     """Handler class to handle updates of custom types.
 
     Attributes:
@@ -78,7 +76,7 @@ class TypeHandler(Handler[UT]):
     def __init__(
         self,
         type: Type[UT],  # pylint: disable=W0622
-        callback: Callable[[UT, 'CallbackContext'], RT],
+        callback: Callable[[UT, CCT], RT],
         strict: bool = False,
         pass_update_queue: bool = False,
         pass_job_queue: bool = False,
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 4f258885005..08bcfac9d87 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -25,7 +25,19 @@
 from signal import SIGABRT, SIGINT, SIGTERM, signal
 from threading import Event, Lock, Thread, current_thread
 from time import sleep
-from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple, Union, no_type_check
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    List,
+    Optional,
+    Tuple,
+    Union,
+    no_type_check,
+    Type,
+    Generic,
+)
 
 from telegram import Bot, TelegramError
 from telegram.error import InvalidToken, RetryAfter, TimedOut, Unauthorized
@@ -33,13 +45,14 @@
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.helpers import get_signal_name
 from telegram.utils.request import Request
+from telegram.utils.types import CCT
 from telegram.utils.webhookhandler import WebhookAppClass, WebhookServer
 
 if TYPE_CHECKING:
     from telegram.ext import BasePersistence, Defaults
 
 
-class Updater:
+class Updater(Generic[CCT]):
     """
     This class, which employs the :class:`telegram.ext.Dispatcher`, provides a frontend to
     :class:`telegram.Bot` to the programmer, so they can focus on coding the bot. Its purpose is to
@@ -94,6 +107,11 @@ class Updater:
             used).
         defaults (:class:`telegram.ext.Defaults`, optional): An object containing default values to
             be used if not set explicitly in the bot methods.
+        custom_context (:obj:`class`, optional): Pass a subclass of
+            :class:`telegram.ext.CallbackContext` to be used instead of
+            :class:`telegram.ext.CallbackContext`, i.e. the ``context`` argument in all the
+            callbacks will be of this type instead. Defaults to
+            :class:`telegram.ext.CallbackContext`.
 
     Note:
         * You must supply either a :attr:`bot` or a :attr:`token` argument.
@@ -120,8 +138,9 @@ def __init__(
         persistence: 'BasePersistence' = None,
         defaults: 'Defaults' = None,
         use_context: bool = True,
-        dispatcher: Dispatcher = None,
+        dispatcher: Dispatcher[CCT] = None,
         base_file_url: str = None,
+        custom_context: Type[CCT] = None,
     ):
 
         if defaults and bot:
@@ -148,6 +167,8 @@ def __init__(
                 raise ValueError('`dispatcher` and `workers` are mutually exclusive')
             if use_context != dispatcher.use_context:
                 raise ValueError('`dispatcher` and `use_context` are mutually exclusive')
+            if custom_context != dispatcher.context_class:
+                raise ValueError('`dispatcher` and `custom_context` are mutually exclusive')
 
         self.logger = logging.getLogger(__name__)
 
@@ -186,7 +207,7 @@ def __init__(
             self.job_queue = JobQueue()
             self.__exception_event = Event()
             self.persistence = persistence
-            self.dispatcher = Dispatcher(
+            self.dispatcher: Dispatcher[CCT] = Dispatcher(
                 self.bot,
                 self.update_queue,
                 job_queue=self.job_queue,
@@ -194,6 +215,7 @@ def __init__(
                 exception_event=self.__exception_event,
                 persistence=persistence,
                 use_context=use_context,
+                custom_context=custom_context,
             )
             self.job_queue.set_dispatcher(self.dispatcher)
         else:
diff --git a/telegram/utils/types.py b/telegram/utils/types.py
index 0a6ba598a1f..8de1262b98c 100644
--- a/telegram/utils/types.py
+++ b/telegram/utils/types.py
@@ -22,6 +22,7 @@
 
 if TYPE_CHECKING:
     from telegram import InputFile
+    from telegram.ext import CallbackContext  # noqa: F401
 
 FileLike = Union[IO, 'InputFile']
 """Either an open file handler or a :class:`telegram.InputFile`."""
@@ -39,3 +40,6 @@
 RT = TypeVar("RT")
 SLT = Union[RT, List[RT], Tuple[RT, ...]]
 """Single instance or list/tuple of instances."""
+
+CCT = TypeVar('CCT', bound='CallbackContext')
+"""An instance of :class:`telegram.ext.CallbackContext` or a custom subclass."""

From 680ef7ae0b7ccded8694491c5919d212fb26d951 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Tue, 22 Dec 2020 14:07:33 +0100
Subject: [PATCH 03/31] Add tests

---
 telegram/ext/dispatcher.py |  4 ++--
 tests/test_dispatcher.py   | 27 +++++++++++++++++++++++++++
 tests/test_jobqueue.py     | 17 ++++++++++++++++-
 tests/test_updater.py      |  6 ++++++
 4 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index 76a7193bfb2..e776f50d9cb 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -166,7 +166,7 @@ class Dispatcher(Generic[CCT]):
 
     @overload
     def __init__(
-        self: 'Dispatcher'['CallbackContext'],  # pylint: disable=E1126
+        self: 'Dispatcher[CallbackContext]',
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
@@ -179,7 +179,7 @@ def __init__(
 
     @overload
     def __init__(
-        self: 'Dispatcher'[CCT],  # pylint: disable=E1126
+        self: 'Dispatcher[CCT]',
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 3ce3f34c605..6c5865d3af9 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -45,6 +45,10 @@ def dp2(bot):
         yield dp
 
 
+class CustomContext(CallbackContext):
+    pass
+
+
 class TestDispatcher:
     message_update = Update(
         1, message=Message(1, None, Chat(1, ''), from_user=User(1, '', False), text='Text')
@@ -804,3 +808,26 @@ def callback(update, context):
         assert cdp.persistence.test_flag_bot_data
         assert not cdp.persistence.test_flag_user_data
         assert cdp.persistence.test_flag_chat_data
+
+    def test_custom_context_error_handler(self, bot):
+        def error_handler(_, context):
+            self.received = type(context)
+
+        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        dispatcher.add_error_handler(error_handler)
+        dispatcher.add_handler(MessageHandler(Filters.all, self.callback_raise_error))
+
+        dispatcher.process_update(self.message_update)
+        sleep(0.1)
+        assert self.received == CustomContext
+
+    def test_custom_context_handler_callback(self, bot):
+        def callback(_, context):
+            self.received = type(context)
+
+        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        dispatcher.add_handler(MessageHandler(Filters.all, callback))
+
+        dispatcher.process_update(self.message_update)
+        sleep(0.1)
+        assert self.received == CustomContext
diff --git a/tests/test_jobqueue.py b/tests/test_jobqueue.py
index 183d1a02b83..622980152a7 100644
--- a/tests/test_jobqueue.py
+++ b/tests/test_jobqueue.py
@@ -28,7 +28,11 @@
 import pytz
 from apscheduler.schedulers import SchedulerNotRunningError
 from flaky import flaky
-from telegram.ext import JobQueue, Updater, Job, CallbackContext
+from telegram.ext import JobQueue, Updater, Job, CallbackContext, Dispatcher
+
+
+class CustomContext(CallbackContext):
+    pass
 
 
 @pytest.fixture(scope='function')
@@ -510,3 +514,14 @@ def test_dispatch_error_that_raises_errors(self, job_queue, dp, caplog):
         assert len(caplog.records) == 1
         rec = caplog.records[-1]
         assert 'No error handlers are registered' in rec.getMessage()
+
+    def test_custom_context(self, bot, job_queue):
+        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        job_queue.set_dispatcher(dispatcher)
+
+        def callback(context):
+            self.result = type(context)
+
+        job_queue.run_once(callback, 0.1)
+        sleep(0.15)
+        assert self.result == CustomContext
diff --git a/tests/test_updater.py b/tests/test_updater.py
index 745836acd3d..5c20db4f01f 100644
--- a/tests/test_updater.py
+++ b/tests/test_updater.py
@@ -580,6 +580,12 @@ def test_mutual_exclude_use_context_dispatcher(self):
         with pytest.raises(ValueError):
             Updater(dispatcher=dispatcher, use_context=use_context)
 
+    def test_mutual_exclude_custom_context_dispatcher(self):
+        dispatcher = Dispatcher(None, None)
+        custom_context = object
+        with pytest.raises(ValueError):
+            Updater(dispatcher=dispatcher, custom_context=custom_context)
+
     def test_defaults_warning(self, bot):
         with pytest.warns(TelegramDeprecationWarning, match='no effect when a Bot is passed'):
             Updater(bot=bot, defaults=Defaults())

From e1eb5850d850a9e74e3e78b4f8b3bcae2640a936 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Tue, 22 Dec 2020 19:38:21 +0100
Subject: [PATCH 04/31] POC for customizing *_data

---
 .../source/telegram.ext.contextcustomizer.rst |   6 +
 docs/source/telegram.ext.rst                  |   1 +
 telegram/ext/__init__.py                      |   2 +
 telegram/ext/basepersistence.py               |  44 +++---
 telegram/ext/callbackcontext.py               |  15 +-
 telegram/ext/contextcustomizer.py             | 128 ++++++++++++++++++
 telegram/ext/dispatcher.py                    | 101 +++++---------
 telegram/ext/jobqueue.py                      |   4 +-
 telegram/ext/updater.py                       |  27 ++--
 telegram/utils/types.py                       |  13 +-
 tests/test_dispatcher.py                      |   9 +-
 tests/test_jobqueue.py                        |   6 +-
 tests/test_updater.py                         |   3 +-
 13 files changed, 242 insertions(+), 117 deletions(-)
 create mode 100644 docs/source/telegram.ext.contextcustomizer.rst
 create mode 100644 telegram/ext/contextcustomizer.py

diff --git a/docs/source/telegram.ext.contextcustomizer.rst b/docs/source/telegram.ext.contextcustomizer.rst
new file mode 100644
index 00000000000..505c2c0c1c7
--- /dev/null
+++ b/docs/source/telegram.ext.contextcustomizer.rst
@@ -0,0 +1,6 @@
+telegram.ext.ContextCustomizer
+==============================
+
+.. autoclass:: telegram.ext.ContextCustomizer
+    :members:
+    :show-inheritance:
diff --git a/docs/source/telegram.ext.rst b/docs/source/telegram.ext.rst
index d5148bd6122..1afa0087f56 100644
--- a/docs/source/telegram.ext.rst
+++ b/docs/source/telegram.ext.rst
@@ -13,6 +13,7 @@ telegram.ext package
     telegram.ext.delayqueue
     telegram.ext.callbackcontext
     telegram.ext.defaults
+    telegram.ext.contextcustomizer
 
 Handlers
 --------
diff --git a/telegram/ext/__init__.py b/telegram/ext/__init__.py
index b614e292c74..0b675d1b0d6 100644
--- a/telegram/ext/__init__.py
+++ b/telegram/ext/__init__.py
@@ -23,6 +23,7 @@
 from .dictpersistence import DictPersistence
 from .handler import Handler
 from .callbackcontext import CallbackContext
+from .contextcustomizer import ContextCustomizer
 from .dispatcher import Dispatcher, DispatcherHandlerStop, run_async
 from .jobqueue import JobQueue, Job
 from .updater import Updater
@@ -79,4 +80,5 @@
     'PollAnswerHandler',
     'PollHandler',
     'Defaults',
+    'ContextCustomizer',
 )
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 378110ed630..f5b9798eaf3 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -20,14 +20,14 @@
 import warnings
 from abc import ABC, abstractmethod
 from copy import copy
-from typing import Any, DefaultDict, Dict, Optional, Tuple, cast, ClassVar
+from typing import Any, DefaultDict, Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping
 
 from telegram import Bot
 
-from telegram.utils.types import ConversationDict
+from telegram.utils.types import ConversationDict, CD, UD, BD, UDM, CDM
 
 
-class BasePersistence(ABC):
+class BasePersistence(ABC, Generic[UD, CD, BD, UDM, CDM]):
     """Interface class for adding persistence to your bot.
     Subclass this object for different implementations of a persistent bot.
 
@@ -84,22 +84,22 @@ def __new__(cls, *args: Any, **kwargs: Any) -> 'BasePersistence':  # pylint: dis
         update_chat_data = instance.update_chat_data
         update_bot_data = instance.update_bot_data
 
-        def get_user_data_insert_bot() -> DefaultDict[int, Dict[Any, Any]]:
+        def get_user_data_insert_bot() -> UDM[int, UD]:
             return instance.insert_bot(get_user_data())
 
-        def get_chat_data_insert_bot() -> DefaultDict[int, Dict[Any, Any]]:
+        def get_chat_data_insert_bot() -> CDM[int, CD]:
             return instance.insert_bot(get_chat_data())
 
-        def get_bot_data_insert_bot() -> Dict[Any, Any]:
+        def get_bot_data_insert_bot() -> BD:
             return instance.insert_bot(get_bot_data())
 
-        def update_user_data_replace_bot(user_id: int, data: Dict) -> None:
+        def update_user_data_replace_bot(user_id: int, data: UD) -> None:
             return update_user_data(user_id, instance.replace_bot(data))
 
-        def update_chat_data_replace_bot(chat_id: int, data: Dict) -> None:
+        def update_chat_data_replace_bot(chat_id: int, data: CD) -> None:
             return update_chat_data(chat_id, instance.replace_bot(data))
 
-        def update_bot_data_replace_bot(data: Dict) -> None:
+        def update_bot_data_replace_bot(data: BD) -> None:
             return update_bot_data(instance.replace_bot(data))
 
         instance.get_user_data = get_user_data_insert_bot
@@ -288,27 +288,27 @@ def _insert_bot(self, obj: object, memo: Dict[int, Any]) -> object:  # pylint: d
         return obj
 
     @abstractmethod
-    def get_user_data(self) -> DefaultDict[int, Dict[Any, Any]]:
+    def get_user_data(self) -> UDM[int, UD]:
         """ "Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``user_data`` if stored, or an empty
-        ``defaultdict(dict)``.
+        ``Mapping`` with integer keys.
 
         Returns:
-            :obj:`defaultdict`: The restored user data.
+            :obj:`Mapping[int, UD]`: The restored user data.
         """
 
     @abstractmethod
-    def get_chat_data(self) -> DefaultDict[int, Dict[Any, Any]]:
+    def get_chat_data(self) -> CDM[int, CD]:
         """ "Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``chat_data`` if stored, or an empty
-        ``defaultdict(dict)``.
+        ``Mapping`` with integer keys.
 
         Returns:
-            :obj:`defaultdict`: The restored chat data.
+            :obj:`Mapping[int, Any]`: The restored chat data.
         """
 
     @abstractmethod
-    def get_bot_data(self) -> Dict[Any, Any]:
+    def get_bot_data(self) -> BD:
         """ "Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``bot_data`` if stored, or an empty
         :obj:`dict`.
@@ -345,32 +345,32 @@ def update_conversation(
         """
 
     @abstractmethod
-    def update_user_data(self, user_id: int, data: Dict) -> None:
+    def update_user_data(self, user_id: int, data: UD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` after a handler has
         handled an update.
 
         Args:
             user_id (:obj:`int`): The user the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
+            data (:obj:`UD`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
         """
 
     @abstractmethod
-    def update_chat_data(self, chat_id: int, data: Dict) -> None:
+    def update_chat_data(self, chat_id: int, data: CD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` after a handler has
         handled an update.
 
         Args:
             chat_id (:obj:`int`): The chat the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
+            data (:obj:`CD`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
         """
 
     @abstractmethod
-    def update_bot_data(self, data: Dict) -> None:
+    def update_bot_data(self, data: BD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` after a handler has
         handled an update.
 
         Args:
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.bot_data` .
+            data (:obj:`BD`): The :attr:`telegram.ext.dispatcher.bot_data` .
         """
 
     def flush(self) -> None:
diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
index 008e20f77f4..3cd816b589c 100644
--- a/telegram/ext/callbackcontext.py
+++ b/telegram/ext/callbackcontext.py
@@ -19,16 +19,17 @@
 # pylint: disable=R0201
 """This module contains the CallbackContext class."""
 from queue import Queue
-from typing import TYPE_CHECKING, Any, Dict, List, Match, NoReturn, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Match, NoReturn, Optional, Tuple, Union, Generic
 
 from telegram import Update
+from telegram.utils.types import UD, CD, BD
 
 if TYPE_CHECKING:
     from telegram import Bot
     from telegram.ext import Dispatcher, Job, JobQueue
 
 
-class CallbackContext:
+class CallbackContext(Generic[UD, CD, BD]):
     """
     This is a context object passed to the callback called by :class:`telegram.ext.Handler`
     or by the :class:`telegram.ext.Dispatcher` in an error handler added by
@@ -88,8 +89,8 @@ def __init__(self, dispatcher: 'Dispatcher'):
             )
         self._dispatcher = dispatcher
         self._bot_data = dispatcher.bot_data
-        self._chat_data: Optional[Dict[Any, Any]] = None
-        self._user_data: Optional[Dict[Any, Any]] = None
+        self._chat_data: Optional[CD] = None
+        self._user_data: Optional[UD] = None
         self.args: Optional[List[str]] = None
         self.matches: Optional[List[Match]] = None
         self.error: Optional[Exception] = None
@@ -103,7 +104,7 @@ def dispatcher(self) -> 'Dispatcher':
         return self._dispatcher
 
     @property
-    def bot_data(self) -> Dict:
+    def bot_data(self) -> BD:
         """
         bot_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
             update it will be the same :obj:`dict`.
@@ -117,7 +118,7 @@ def bot_data(self, value: Any) -> NoReturn:
         )
 
     @property
-    def chat_data(self) -> Optional[Dict]:
+    def chat_data(self) -> Optional[CD]:
         """
 
         chat_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
@@ -138,7 +139,7 @@ def chat_data(self, value: Any) -> NoReturn:
         )
 
     @property
-    def user_data(self) -> Optional[Dict]:
+    def user_data(self) -> Optional[UD]:
         """
         user_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
             update from the same user it will be the same :obj:`dict`.
diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
new file mode 100644
index 00000000000..0d8e5fb4281
--- /dev/null
+++ b/telegram/ext/contextcustomizer.py
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+#
+# A library that provides a Python interface to the Telegram Bot API
+# Copyright (C) 2020
+# Leandro Toledo de Souza <devs@python-telegram-bot.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser Public License for more details.
+#
+# You should have received a copy of the GNU Lesser Public License
+# along with this program.  If not, see [http://www.gnu.org/licenses/].
+"""This module contains the auxiliary class ContextCustomizer."""
+from collections import defaultdict, Mapping
+from typing import Type, Optional, Any, NoReturn, Generic
+
+from telegram.ext.callbackcontext import CallbackContext
+from telegram.utils.types import CCT, UD, CD, BD, CDM, UDM
+
+
+class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
+    """
+    Convenience class to gather customizable types of the ``context`` interface.
+
+    Args:
+        context (:obj:`type`, optional): Determines the type of the ``context`` argument of all
+            (error-)handler callbacks and job callbacks. Must be a subclass of
+            :class:`telegram.ext.CallbackContext`. Defaults to
+            :class:`telegram.ext.CallbackContext`.
+        bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            instantiating without arguments
+        chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+        user_data (:obj:`type`, optional): Determines the type of ``context.user_data` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+        chat_data_mapping (:obj:`type`, optional): In combination with :attr:`chat_data` determines
+            the type of :attr:`telegram.ext.Dispatcher.chat_data`. Must support instantiating via
+
+            .. code:: python
+
+                chat_data_mapping(chat_data)
+
+        user_data_mapping (:obj:`type`, optional): In combination with :attr:`user_data` determines
+            the type of :attr:`telegram.ext.Dispatcher.user_data`. Must support instantiating via
+
+            .. code:: python
+
+                user_data_mapping(user_data)
+
+    """
+
+    def __init__(
+        self,
+        context: Type[CCT] = CallbackContext,
+        bot_data: Type[BD] = dict,
+        chat_data: Type[CD] = dict,
+        user_data: Type[UD] = dict,
+        chat_data_mapping: Type[CDM] = defaultdict,
+        user_data_mapping: Type[UDM] = defaultdict,
+    ):
+        if not issubclass(context, CallbackContext):
+            raise ValueError('context must be a subclass of CallbackContext.')
+        if not issubclass(chat_data_mapping, Mapping):
+            raise ValueError('chat_data_mapping must be a subclass of collections.Mapping.')
+        if not issubclass(user_data_mapping, Mapping):
+            raise ValueError('user_data_mapping must be a subclass of collections.Mapping.')
+
+        self._context = context
+        self._bot_data = bot_data
+        self._chat_data = chat_data
+        self._user_data = user_data
+        self._chat_data_mapping = chat_data_mapping
+        self._user_data_mapping = user_data_mapping
+
+    @property
+    def context(self) -> Optional[Type]:
+        return self._context
+
+    @context.setter
+    def context(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
+
+    @property
+    def bot_data(self) -> Optional[Type]:
+        return self._bot_data
+
+    @bot_data.setter
+    def bot_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
+
+    @property
+    def chat_data(self) -> Optional[Type]:
+        return self._chat_data
+
+    @chat_data.setter
+    def chat_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
+
+    @property
+    def user_data(self) -> Optional[Type]:
+        return self._user_data
+
+    @user_data.setter
+    def user_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
+
+    @property
+    def user_data_mapping(self) -> Optional[Type]:
+        return self._user_data_mapping
+
+    @user_data_mapping.setter
+    def user_data_mapping(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
+
+    @property
+    def chat_data_mapping(self) -> Optional[Type]:
+        return self._chat_data_mapping
+
+    @chat_data_mapping.setter
+    def chat_data_mapping(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index e776f50d9cb..8300d2ca9cc 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -21,7 +21,6 @@
 import logging
 import warnings
 import weakref
-from collections import defaultdict
 from functools import wraps
 from queue import Empty, Queue
 from threading import BoundedSemaphore, Event, Lock, Thread, current_thread
@@ -30,28 +29,24 @@
     TYPE_CHECKING,
     Any,
     Callable,
-    DefaultDict,
     Dict,
     List,
     Optional,
     Set,
     Union,
     Generic,
-    Type,
     TypeVar,
-    overload,
 )
 from uuid import uuid4
 
 from telegram import TelegramError, Update
-from telegram.ext import BasePersistence
+from telegram.ext import BasePersistence, ContextCustomizer
 from telegram.ext.callbackcontext import CallbackContext
 from telegram.ext.handler import Handler
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
-from telegram.utils.types import CCT
-
+from telegram.utils.types import CCT, UD, CD, BD, UDM, CDM
 
 if TYPE_CHECKING:
     from telegram import Bot
@@ -121,7 +116,7 @@ def __init__(self, state: object = None) -> None:
         self.state = state
 
 
-class Dispatcher(Generic[CCT]):
+class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
     """This class dispatches all kinds of updates to its registered handlers.
 
     Attributes:
@@ -136,8 +131,8 @@ class Dispatcher(Generic[CCT]):
         bot_data (:obj:`dict`): A dictionary handlers can use to store data for the bot.
         persistence (:class:`telegram.ext.BasePersistence`): Optional. The persistence class to
             store data that should be persistent over restarts.
-        context_class (:obj:`class`): The class to use for the ``context`` argument of the
-            callbacks.
+        context_customizer (:class:`telegram.ext.ContextCustomizer`): Container for the types used
+            in the ``context`` interface.
 
     Args:
         bot (:class:`telegram.Bot`): The bot object that should be passed to the handlers.
@@ -151,11 +146,10 @@ class Dispatcher(Generic[CCT]):
         use_context (:obj:`bool`, optional): If set to :obj:`True` uses the context based callback
             API (ignored if `dispatcher` argument is used). Defaults to :obj:`True`.
             **New users**: set this to :obj:`True`.
-        custom_context (:obj:`class`, optional): Pass a subclass of
-            :class:`telegram.ext.CallbackContext` to be used instead of
-            :class:`telegram.ext.CallbackContext`, i.e. the ``context`` argument in all the
-            callbacks will be of this type instead. Defaults to
-            :class:`telegram.ext.CallbackContext`.
+        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
+            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+            ``context`` interface. If not passed, the defaults documented in
+            :class:`telegram.ext.ContextCustomizer` will be used.
 
     """
 
@@ -164,33 +158,6 @@ class Dispatcher(Generic[CCT]):
     __singleton = None
     logger = logging.getLogger(__name__)
 
-    @overload
-    def __init__(
-        self: 'Dispatcher[CallbackContext]',
-        bot: 'Bot',
-        update_queue: Queue,
-        workers: int = 4,
-        exception_event: Event = None,
-        job_queue: 'JobQueue' = None,
-        persistence: BasePersistence = None,
-        use_context: bool = True,
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: 'Dispatcher[CCT]',
-        bot: 'Bot',
-        update_queue: Queue,
-        workers: int = 4,
-        exception_event: Event = None,
-        job_queue: 'JobQueue' = None,
-        persistence: BasePersistence = None,
-        use_context: bool = True,
-        custom_context: Type[CCT] = None,
-    ):
-        ...
-
     def __init__(
         self,
         bot: 'Bot',
@@ -198,15 +165,16 @@ def __init__(
         workers: int = 4,
         exception_event: Event = None,
         job_queue: 'JobQueue' = None,
-        persistence: BasePersistence = None,
+        persistence: BasePersistence[UD, CD, BD, UDM, CDM] = None,
         use_context: bool = True,
-        custom_context: Type[CCT] = None,
+        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = ContextCustomizer(),
     ):
         self.bot = bot
         self.update_queue = update_queue
         self.job_queue = job_queue
         self.workers = workers
         self.use_context = use_context
+        self.context_customizer = context_customizer
 
         if not use_context:
             warnings.warn(
@@ -214,20 +182,14 @@ def __init__(
                 TelegramDeprecationWarning,
                 stacklevel=3,
             )
-        if not use_context and custom_context:
-            raise ValueError(
-                'Custom CallbackContext classes can only be used, when use_context=True.'
-            )
-        if custom_context:
-            if not issubclass(custom_context, CallbackContext):
-                raise ValueError('custom_context must be a subclass of CallbackContext')
-            self.context_class = custom_context
-        else:
-            self.context_class = CallbackContext  # type: ignore[assignment]
 
-        self.user_data: DefaultDict[int, Dict[Any, Any]] = defaultdict(dict)
-        self.chat_data: DefaultDict[int, Dict[Any, Any]] = defaultdict(dict)
-        self.bot_data = {}
+        self.user_data = self.context_customizer.user_data_mapping(
+            self.context_customizer.user_data
+        )
+        self.chat_data = self.context_customizer.chat_data_mapping(
+            self.context_customizer.chat_data
+        )
+        self.bot_data = self.context_customizer.bot_data()
         self.persistence: Optional[BasePersistence] = None
         self._update_persistence_lock = Lock()
         if persistence:
@@ -237,16 +199,25 @@ def __init__(
             self.persistence.set_bot(self.bot)
             if self.persistence.store_user_data:
                 self.user_data = self.persistence.get_user_data()
-                if not isinstance(self.user_data, defaultdict):
-                    raise ValueError("user_data must be of type defaultdict")
+                if not isinstance(self.user_data, self.context_customizer.user_data_mapping):
+                    raise ValueError(
+                        f"user_data must be of type "
+                        f"{self.context_customizer.user_data_mapping.__name__}"
+                    )
             if self.persistence.store_chat_data:
                 self.chat_data = self.persistence.get_chat_data()
-                if not isinstance(self.chat_data, defaultdict):
-                    raise ValueError("chat_data must be of type defaultdict")
+                if not isinstance(self.chat_data, self.context_customizer.chat_data_mapping):
+                    raise ValueError(
+                        f"chat_data must be of type "
+                        f"{self.context_customizer.chat_data_mapping.__name__}"
+                    )
             if self.persistence.store_bot_data:
                 self.bot_data = self.persistence.get_bot_data()
-                if not isinstance(self.bot_data, dict):
-                    raise ValueError("bot_data must be of type dict")
+                if not isinstance(self.bot_data, self.context_customizer.bot_data):
+                    raise ValueError(
+                        f"bot_data must be of type {self.context_customizer.bot_data.__name__}"
+                    )
+
         else:
             self.persistence = None
 
@@ -490,7 +461,7 @@ def process_update(self, update: Union[str, Update, TelegramError]) -> None:
                     check = handler.check_update(update)
                     if check is not None and check is not False:
                         if not context and self.use_context:
-                            context = self.context_class.from_update(update, self)
+                            context = self.context_customizer.context.from_update(update, self)
                         handler.handle_update(update, self, check, context)
 
                         # If handler runs async updating immediately doesn't make sense
@@ -719,7 +690,7 @@ def dispatch_error(
         if self.error_handlers:
             for callback, run_async in self.error_handlers.items():  # pylint: disable=W0621
                 if self.use_context:
-                    context = self.context_class.from_error(
+                    context = self.context_customizer.context.from_error(
                         update, error, self, async_args=async_args, async_kwargs=async_kwargs
                     )
                     if run_async:
diff --git a/telegram/ext/jobqueue.py b/telegram/ext/jobqueue.py
index 8c391570884..a06659f969a 100644
--- a/telegram/ext/jobqueue.py
+++ b/telegram/ext/jobqueue.py
@@ -70,7 +70,7 @@ def aps_log_filter(record):  # type: ignore
 
     def _build_args(self, job: 'Job') -> List[Union[CallbackContext, 'Bot', 'Job']]:
         if self._dispatcher.use_context:
-            return [self._dispatcher.context_class.from_job(job, self._dispatcher)]
+            return [self._dispatcher.context_customizer.context.from_job(job, self._dispatcher)]
         return [self._dispatcher.bot, job]
 
     def _tz_now(self) -> datetime.datetime:
@@ -568,7 +568,7 @@ def run(self, dispatcher: 'Dispatcher') -> None:
         """Executes the callback function independently of the jobs schedule."""
         try:
             if dispatcher.use_context:
-                self.callback(dispatcher.context_class.from_job(self, dispatcher))
+                self.callback(dispatcher.context_customizer.context.from_job(self, dispatcher))
             else:
                 self.callback(dispatcher.bot, self)  # type: ignore[arg-type,call-arg]
         except Exception as exc:
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 08bcfac9d87..00085cb1c66 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -41,18 +41,18 @@
 
 from telegram import Bot, TelegramError
 from telegram.error import InvalidToken, RetryAfter, TimedOut, Unauthorized
-from telegram.ext import Dispatcher, JobQueue
+from telegram.ext import Dispatcher, JobQueue, ContextCustomizer
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.helpers import get_signal_name
 from telegram.utils.request import Request
-from telegram.utils.types import CCT
+from telegram.utils.types import CCT, UD, BD, UDM, CDM, CD
 from telegram.utils.webhookhandler import WebhookAppClass, WebhookServer
 
 if TYPE_CHECKING:
     from telegram.ext import BasePersistence, Defaults
 
 
-class Updater(Generic[CCT]):
+class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
     """
     This class, which employs the :class:`telegram.ext.Dispatcher`, provides a frontend to
     :class:`telegram.Bot` to the programmer, so they can focus on coding the bot. Its purpose is to
@@ -107,11 +107,10 @@ class Updater(Generic[CCT]):
             used).
         defaults (:class:`telegram.ext.Defaults`, optional): An object containing default values to
             be used if not set explicitly in the bot methods.
-        custom_context (:obj:`class`, optional): Pass a subclass of
-            :class:`telegram.ext.CallbackContext` to be used instead of
-            :class:`telegram.ext.CallbackContext`, i.e. the ``context`` argument in all the
-            callbacks will be of this type instead. Defaults to
-            :class:`telegram.ext.CallbackContext`.
+        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
+            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+            ``context`` interface. If not passed, the defaults documented in
+            :class:`telegram.ext.ContextCustomizer` will be used.
 
     Note:
         * You must supply either a :attr:`bot` or a :attr:`token` argument.
@@ -135,12 +134,12 @@ def __init__(
         private_key_password: bytes = None,
         user_sig_handler: Callable = None,
         request_kwargs: Dict[str, Any] = None,
-        persistence: 'BasePersistence' = None,
+        persistence: 'BasePersistence[UD, CD, BD, UDM, CDM]' = None,
         defaults: 'Defaults' = None,
         use_context: bool = True,
-        dispatcher: Dispatcher[CCT] = None,
+        dispatcher: Dispatcher[CCT, UD, CD, BD, UDM, CDM] = None,
         base_file_url: str = None,
-        custom_context: Type[CCT] = None,
+        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
     ):
 
         if defaults and bot:
@@ -167,8 +166,8 @@ def __init__(
                 raise ValueError('`dispatcher` and `workers` are mutually exclusive')
             if use_context != dispatcher.use_context:
                 raise ValueError('`dispatcher` and `use_context` are mutually exclusive')
-            if custom_context != dispatcher.context_class:
-                raise ValueError('`dispatcher` and `custom_context` are mutually exclusive')
+            if context_customizer is not None:
+                raise ValueError('`dispatcher` and `context_customizer` are mutually exclusive')
 
         self.logger = logging.getLogger(__name__)
 
@@ -215,7 +214,7 @@ def __init__(
                 exception_event=self.__exception_event,
                 persistence=persistence,
                 use_context=use_context,
-                custom_context=custom_context,
+                context_customizer=context_customizer or ContextCustomizer(),
             )
             self.job_queue.set_dispatcher(self.dispatcher)
         else:
diff --git a/telegram/utils/types.py b/telegram/utils/types.py
index 8de1262b98c..80e4e2f8680 100644
--- a/telegram/utils/types.py
+++ b/telegram/utils/types.py
@@ -18,7 +18,7 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains custom typing aliases."""
 from pathlib import Path
-from typing import IO, TYPE_CHECKING, Any, Dict, List, Optional, Tuple, TypeVar, Union
+from typing import IO, TYPE_CHECKING, Any, Dict, List, Optional, Tuple, TypeVar, Union, Mapping
 
 if TYPE_CHECKING:
     from telegram import InputFile
@@ -43,3 +43,14 @@
 
 CCT = TypeVar('CCT', bound='CallbackContext')
 """An instance of :class:`telegram.ext.CallbackContext` or a custom subclass."""
+
+UD = TypeVar('UD')
+"""Type of the user data for a single user."""
+CD = TypeVar('CD')
+"""Type of the chat data for a single user."""
+BD = TypeVar('BD')
+"""Type of the bot data."""
+UDM = TypeVar('UDM', bound=Mapping)
+"""Type of the user data mapping."""
+CDM = TypeVar('CDM', bound=Mapping)
+"""Type of the chat data mapping."""
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 6c5865d3af9..f327a4b721d 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -32,6 +32,7 @@
     CallbackContext,
     JobQueue,
     BasePersistence,
+    ContextCustomizer,
 )
 from telegram.ext.dispatcher import run_async, Dispatcher, DispatcherHandlerStop
 from telegram.utils.deprecate import TelegramDeprecationWarning
@@ -813,7 +814,9 @@ def test_custom_context_error_handler(self, bot):
         def error_handler(_, context):
             self.received = type(context)
 
-        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        dispatcher = Dispatcher(
+            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+        )
         dispatcher.add_error_handler(error_handler)
         dispatcher.add_handler(MessageHandler(Filters.all, self.callback_raise_error))
 
@@ -825,7 +828,9 @@ def test_custom_context_handler_callback(self, bot):
         def callback(_, context):
             self.received = type(context)
 
-        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        dispatcher = Dispatcher(
+            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+        )
         dispatcher.add_handler(MessageHandler(Filters.all, callback))
 
         dispatcher.process_update(self.message_update)
diff --git a/tests/test_jobqueue.py b/tests/test_jobqueue.py
index 622980152a7..709d41e96a5 100644
--- a/tests/test_jobqueue.py
+++ b/tests/test_jobqueue.py
@@ -28,7 +28,7 @@
 import pytz
 from apscheduler.schedulers import SchedulerNotRunningError
 from flaky import flaky
-from telegram.ext import JobQueue, Updater, Job, CallbackContext, Dispatcher
+from telegram.ext import JobQueue, Updater, Job, CallbackContext, Dispatcher, ContextCustomizer
 
 
 class CustomContext(CallbackContext):
@@ -516,7 +516,9 @@ def test_dispatch_error_that_raises_errors(self, job_queue, dp, caplog):
         assert 'No error handlers are registered' in rec.getMessage()
 
     def test_custom_context(self, bot, job_queue):
-        dispatcher = Dispatcher(bot, Queue(), custom_context=CustomContext)
+        dispatcher = Dispatcher(
+            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+        )
         job_queue.set_dispatcher(dispatcher)
 
         def callback(context):
diff --git a/tests/test_updater.py b/tests/test_updater.py
index 5c20db4f01f..ad9353b665c 100644
--- a/tests/test_updater.py
+++ b/tests/test_updater.py
@@ -582,9 +582,8 @@ def test_mutual_exclude_use_context_dispatcher(self):
 
     def test_mutual_exclude_custom_context_dispatcher(self):
         dispatcher = Dispatcher(None, None)
-        custom_context = object
         with pytest.raises(ValueError):
-            Updater(dispatcher=dispatcher, custom_context=custom_context)
+            Updater(dispatcher=dispatcher, context_customizer=True)
 
     def test_defaults_warning(self, bot):
         with pytest.warns(TelegramDeprecationWarning, match='no effect when a Bot is passed'):

From 9189994f3bdfaccb56368796763d04f541e1ec87 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 15 Jan 2021 17:03:53 +0100
Subject: [PATCH 05/31] Get typing to work to reasonable accuracy

---
 telegram/ext/basepersistence.py   |  11 +-
 telegram/ext/contextcustomizer.py | 584 +++++++++++++++++++++++++++++-
 telegram/ext/dispatcher.py        |  39 +-
 telegram/ext/handler.py           |   8 +-
 telegram/ext/updater.py           |  85 ++++-
 telegram/utils/types.py           |  13 +-
 6 files changed, 702 insertions(+), 38 deletions(-)

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 385c19d2f0e..5a60994f805 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -19,8 +19,9 @@
 """This module contains the BasePersistence class."""
 import warnings
 from abc import ABC, abstractmethod
+from collections.abc import Mapping
 from copy import copy
-from typing import Any, DefaultDict, Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping
+from typing import Any, Dict, Optional, Tuple, cast, ClassVar, Generic
 
 from telegram import Bot
 
@@ -84,10 +85,10 @@ def __new__(cls, *args: Any, **kwargs: Any) -> 'BasePersistence':  # pylint: dis
         update_chat_data = instance.update_chat_data
         update_bot_data = instance.update_bot_data
 
-        def get_user_data_insert_bot() -> UDM[int, UD]:
+        def get_user_data_insert_bot() -> Mapping[int, UD]:
             return instance.insert_bot(get_user_data())
 
-        def get_chat_data_insert_bot() -> CDM[int, CD]:
+        def get_chat_data_insert_bot() -> Mapping[int, CD]:
             return instance.insert_bot(get_chat_data())
 
         def get_bot_data_insert_bot() -> BD:
@@ -288,7 +289,7 @@ def _insert_bot(self, obj: object, memo: Dict[int, Any]) -> object:  # pylint: d
         return obj
 
     @abstractmethod
-    def get_user_data(self) -> UDM[int, UD]:
+    def get_user_data(self) -> Mapping[int, UD]:
         """ "Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``user_data`` if stored, or an empty
         ``Mapping`` with integer keys.
@@ -298,7 +299,7 @@ def get_user_data(self) -> UDM[int, UD]:
         """
 
     @abstractmethod
-    def get_chat_data(self) -> CDM[int, CD]:
+    def get_chat_data(self) -> Mapping[int, CD]:
         """ "Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``chat_data`` if stored, or an empty
         ``Mapping`` with integer keys.
diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
index 0d8e5fb4281..f2bfd00cfef 100644
--- a/telegram/ext/contextcustomizer.py
+++ b/telegram/ext/contextcustomizer.py
@@ -16,9 +16,11 @@
 #
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
+# pylint: disable=R0201
 """This module contains the auxiliary class ContextCustomizer."""
-from collections import defaultdict, Mapping
-from typing import Type, Optional, Any, NoReturn, Generic
+from collections import defaultdict
+from collections.abc import Mapping
+from typing import Type, Optional, Any, NoReturn, Generic, overload
 
 from telegram.ext.callbackcontext import CallbackContext
 from telegram.utils.types import CCT, UD, CD, BD, CDM, UDM
@@ -56,14 +58,580 @@ class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     """
 
+    # Overload signature were autogenerated with https://git.io/JtJPj
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, dict, defaultdict, defaultdict]",
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, dict, defaultdict, defaultdict]",
+        context: Type[CCT],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, dict, defaultdict, defaultdict]",
+        bot_data: Type[UD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, dict, defaultdict, defaultdict]",
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, BD, defaultdict, defaultdict]",
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, dict, UDM, defaultdict]",
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, dict, defaultdict, CDM]",
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, dict, defaultdict, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, dict, defaultdict, defaultdict]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, BD, defaultdict, defaultdict]",
+        context: Type[CCT],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, dict, UDM, defaultdict]",
+        context: Type[CCT],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, dict, defaultdict, CDM]",
+        context: Type[CCT],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, dict, defaultdict, defaultdict]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, BD, defaultdict, defaultdict]",
+        bot_data: Type[UD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, dict, UDM, defaultdict]",
+        bot_data: Type[UD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
     def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, dict, defaultdict, CDM]",
+        bot_data: Type[UD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, BD, defaultdict, defaultdict]",
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, dict, UDM, defaultdict]",
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, dict, defaultdict, CDM]",
+        chat_data: Type[CD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, BD, UDM, defaultdict]",
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, BD, defaultdict, CDM]",
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, dict, UDM, CDM]",
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, dict, defaultdict, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, BD, defaultdict, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, dict, UDM, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, dict, defaultdict, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, BD, defaultdict, defaultdict]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, dict, UDM, defaultdict]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, dict, defaultdict, CDM]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, BD, UDM, defaultdict]",
+        context: Type[CCT],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, BD, defaultdict, CDM]",
+        context: Type[CCT],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, dict, UDM, CDM]",
+        context: Type[CCT],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, BD, defaultdict, defaultdict]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, dict, UDM, defaultdict]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, dict, defaultdict, CDM]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, BD, UDM, defaultdict]",
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, BD, defaultdict, CDM]",
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, dict, UDM, CDM]",
+        bot_data: Type[UD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, BD, UDM, defaultdict]",
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, BD, defaultdict, CDM]",
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, dict, UDM, CDM]",
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, dict, BD, UDM, CDM]",
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, BD, defaultdict, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, dict, UDM, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, dict, defaultdict, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, BD, UDM, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, BD, defaultdict, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, dict, UDM, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, BD, UDM, defaultdict]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, BD, defaultdict, CDM]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, dict, UDM, CDM]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, dict, BD, UDM, CDM]",
+        context: Type[CCT],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, BD, UDM, defaultdict]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, BD, defaultdict, CDM]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, dict, UDM, CDM]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, dict, BD, UDM, CDM]",
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, dict, CD, BD, UDM, CDM]",
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, defaultdict]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, BD, defaultdict, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, dict, UDM, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, dict, BD, UDM, CDM]",
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, dict, CD, BD, UDM, CDM]",
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CallbackContext, UD, CD, BD, UDM, CDM]",
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
+    def __init__(  # type: ignore[no-untyped-def]
         self,
-        context: Type[CCT] = CallbackContext,
-        bot_data: Type[BD] = dict,
-        chat_data: Type[CD] = dict,
-        user_data: Type[UD] = dict,
-        chat_data_mapping: Type[CDM] = defaultdict,
-        user_data_mapping: Type[UDM] = defaultdict,
+        context=CallbackContext,
+        bot_data=dict,
+        chat_data=dict,
+        user_data=dict,
+        chat_data_mapping=defaultdict,
+        user_data_mapping=defaultdict,
     ):
         if not issubclass(context, CallbackContext):
             raise ValueError('context must be a subclass of CallbackContext.')
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index 1cc1a4cb63f..5c9c76c04ed 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -36,6 +36,7 @@
     Union,
     Generic,
     TypeVar,
+    overload,
 )
 from uuid import uuid4
 
@@ -49,6 +50,7 @@
 from telegram.utils.types import CCT, UD, CD, BD, UDM, CDM
 
 if TYPE_CHECKING:
+    from collections import defaultdict
     from telegram import Bot
     from telegram.ext import JobQueue
 
@@ -158,16 +160,45 @@ class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
     __singleton = None
     logger = logging.getLogger(__name__)
 
+    @overload
     def __init__(
+        self: 'Dispatcher[CallbackContext, dict, dict, dict, defaultdict, defaultdict]',
+        bot: 'Bot',
+        update_queue: Queue,
+        workers: int = 4,
+        exception_event: Event = None,
+        job_queue: 'JobQueue' = None,
+        persistence: BasePersistence = None,
+        use_context: bool = True,
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'Dispatcher[CCT, UD, CD, BD, UDM, CDM]',
+        bot: 'Bot',
+        update_queue: Queue,
+        workers: int = 4,
+        exception_event: Event = None,
+        job_queue: 'JobQueue' = None,
+        persistence: BasePersistence = None,
+        use_context: bool = True,
+        context_customizer: ContextCustomizer[
+            CCT, UD, CD, BD, UDM, CDM
+        ] = ContextCustomizer(),  # type: ignore[assignment]
+    ):
+        ...
+
+    def __init__(  # type: ignore[no-untyped-def]
         self,
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
         exception_event: Event = None,
         job_queue: 'JobQueue' = None,
-        persistence: BasePersistence[UD, CD, BD, UDM, CDM] = None,
+        persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = ContextCustomizer(),
+        context_customizer=ContextCustomizer(),
     ):
         self.bot = bot
         self.update_queue = update_queue
@@ -643,7 +674,7 @@ def __update_persistence(self, update: Any = None) -> None:
 
     def add_error_handler(
         self,
-        callback: Callable[[Any, CCT], None],
+        callback: Callable[[object, CCT], None],
         run_async: Union[bool, DefaultValue] = DEFAULT_FALSE,  # pylint: disable=W0621
     ) -> None:
         """Registers an error handler in the Dispatcher. This handler will receive every error
@@ -679,7 +710,7 @@ def add_error_handler(
 
         self.error_handlers[callback] = run_async
 
-    def remove_error_handler(self, callback: Callable[[Any, CCT], None]) -> None:
+    def remove_error_handler(self, callback: Callable[[object, CCT], None]) -> None:
         """Removes an error handler.
 
         Args:
diff --git a/telegram/ext/handler.py b/telegram/ext/handler.py
index ccdc4de5e15..5764ebaad2b 100644
--- a/telegram/ext/handler.py
+++ b/telegram/ext/handler.py
@@ -211,13 +211,9 @@ def collect_optional_args(
             optional_args['job_queue'] = dispatcher.job_queue
         if self.pass_user_data and isinstance(update, Update):
             user = update.effective_user
-            optional_args['user_data'] = dispatcher.user_data[
-                user.id if user else None  # type: ignore[index]
-            ]
+            optional_args['user_data'] = dispatcher.user_data[user.id if user else None]
         if self.pass_chat_data and isinstance(update, Update):
             chat = update.effective_chat
-            optional_args['chat_data'] = dispatcher.chat_data[
-                chat.id if chat else None  # type: ignore[index]
-            ]
+            optional_args['chat_data'] = dispatcher.chat_data[chat.id if chat else None]
 
         return optional_args
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index baea2ea74d6..65d3f93923b 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -35,8 +35,8 @@
     Tuple,
     Union,
     no_type_check,
-    Type,
     Generic,
+    overload,
 )
 
 from telegram import Bot, TelegramError
@@ -49,7 +49,8 @@
 from telegram.utils.webhookhandler import WebhookAppClass, WebhookServer
 
 if TYPE_CHECKING:
-    from telegram.ext import BasePersistence, Defaults
+    from collections import defaultdict
+    from telegram.ext import BasePersistence, Defaults, CallbackContext
 
 
 class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
@@ -124,8 +125,9 @@ class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     _request = None
 
+    @overload
     def __init__(
-        self,
+        self: 'Updater[CallbackContext, dict, dict, dict, defaultdict, defaultdict]',
         token: str = None,
         base_url: str = None,
         workers: int = 4,
@@ -134,10 +136,54 @@ def __init__(
         private_key_password: bytes = None,
         user_sig_handler: Callable = None,
         request_kwargs: Dict[str, Any] = None,
-        persistence: 'BasePersistence[UD, CD, BD, UDM, CDM]' = None,
+        persistence: BasePersistence = None,  # pylint: disable=E0601
         defaults: 'Defaults' = None,
         use_context: bool = True,
+        base_file_url: str = None,
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'Updater[CCT, UD, CD, BD, UDM, CDM]',
+        token: str = None,
+        base_url: str = None,
+        workers: int = 4,
+        bot: Bot = None,
+        private_key: bytes = None,
+        private_key_password: bytes = None,
+        user_sig_handler: Callable = None,
+        request_kwargs: Dict[str, Any] = None,
+        persistence: BasePersistence = None,
+        defaults: 'Defaults' = None,
+        use_context: bool = True,
+        base_file_url: str = None,
+        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'Updater[CCT, UD, CD, BD, UDM, CDM]',
+        user_sig_handler: Callable = None,
         dispatcher: Dispatcher[CCT, UD, CD, BD, UDM, CDM] = None,
+    ):
+        ...
+
+    def __init__(  # type: ignore[no-untyped-def,misc]
+        self,
+        token: str = None,
+        base_url: str = None,
+        workers: int = 4,
+        bot: Bot = None,
+        private_key: bytes = None,
+        private_key_password: bytes = None,
+        user_sig_handler: Callable = None,
+        request_kwargs: Dict[str, Any] = None,
+        persistence: BasePersistence = None,
+        defaults: 'Defaults' = None,
+        use_context: bool = True,
+        dispatcher=None,
         base_file_url: str = None,
         context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
     ):
@@ -206,16 +252,27 @@ def __init__(
             self.job_queue = JobQueue()
             self.__exception_event = Event()
             self.persistence = persistence
-            self.dispatcher: Dispatcher[CCT] = Dispatcher(
-                self.bot,
-                self.update_queue,
-                job_queue=self.job_queue,
-                workers=workers,
-                exception_event=self.__exception_event,
-                persistence=persistence,
-                use_context=use_context,
-                context_customizer=context_customizer or ContextCustomizer(),
-            )
+            if context_customizer:
+                self.dispatcher = Dispatcher(
+                    self.bot,
+                    self.update_queue,
+                    job_queue=self.job_queue,
+                    workers=workers,
+                    exception_event=self.__exception_event,
+                    persistence=persistence,
+                    use_context=use_context,
+                    context_customizer=context_customizer,
+                )
+            else:
+                self.dispatcher = Dispatcher(  # type: ignore[assignment]
+                    self.bot,
+                    self.update_queue,
+                    job_queue=self.job_queue,
+                    workers=workers,
+                    exception_event=self.__exception_event,
+                    persistence=persistence,
+                    use_context=use_context,
+                )
             self.job_queue.set_dispatcher(self.dispatcher)
         else:
             con_pool_size = dispatcher.workers + 4
diff --git a/telegram/utils/types.py b/telegram/utils/types.py
index 226111f745c..7dd31211889 100644
--- a/telegram/utils/types.py
+++ b/telegram/utils/types.py
@@ -18,7 +18,18 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains custom typing aliases."""
 from pathlib import Path
-from typing import IO, TYPE_CHECKING, Any, Dict, List, Optional, Tuple, TypeVar, Union, Mapping
+from typing import (
+    IO,
+    TYPE_CHECKING,
+    Any,
+    Dict,
+    List,
+    Optional,
+    Tuple,
+    TypeVar,
+    Union,
+    Mapping,
+)
 
 if TYPE_CHECKING:
     from telegram import InputFile

From 254fe2def5a53eb5d433d2719e24ef7f879a8d9b Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sat, 16 Jan 2021 16:31:26 +0100
Subject: [PATCH 06/31] Improve type hints some more

---
 telegram/ext/contextcustomizer.py | 289 ++++++++++++++++--------------
 telegram/ext/dispatcher.py        |  20 ++-
 telegram/utils/types.py           |   5 +
 3 files changed, 167 insertions(+), 147 deletions(-)

diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
index f2bfd00cfef..98c5e771092 100644
--- a/telegram/ext/contextcustomizer.py
+++ b/telegram/ext/contextcustomizer.py
@@ -20,10 +20,10 @@
 """This module contains the auxiliary class ContextCustomizer."""
 from collections import defaultdict
 from collections.abc import Mapping
-from typing import Type, Optional, Any, NoReturn, Generic, overload
+from typing import Type, Any, NoReturn, Generic, overload, Dict  # pylint: disable=W0611
 
 from telegram.ext.callbackcontext import CallbackContext
-from telegram.utils.types import CCT, UD, CD, BD, CDM, UDM
+from telegram.utils.types import CCT, UD, CD, BD, CDM, UDM, IntDD  # pylint: disable=W0611
 
 
 class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
@@ -36,12 +36,12 @@ class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
             :class:`telegram.ext.CallbackContext`. Defaults to
             :class:`telegram.ext.CallbackContext`.
         bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`. Must support
             instantiating without arguments
         chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`.
         user_data (:obj:`type`, optional): Determines the type of ``context.user_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`.
         chat_data_mapping (:obj:`type`, optional): In combination with :attr:`chat_data` determines
             the type of :attr:`telegram.ext.Dispatcher.chat_data`. Must support instantiating via
 
@@ -58,67 +58,71 @@ class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     """
 
-    # Overload signature were autogenerated with https://git.io/JtJPj
-
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, "
+        "IntDD[Dict], IntDD[Dict]]",
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, Dict, Dict, IntDD[Dict], IntDD[Dict]]",
         context: Type[CCT],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, dict, defaultdict, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
+        "IntDD[UD], IntDD[Dict]]",
+        bot_data: Type[BD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
+        "IntDD[Dict], IntDD[CD]]",
         chat_data: Type[CD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, BD, defaultdict, defaultdict]",
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, "
+        "IntDD[Dict], IntDD[Dict]]",
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, "
+        "Dict, UDM, IntDD[Dict]]",
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, "
+        "IntDD[Dict], CDM]",
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, Dict, Dict, IntDD[UD], IntDD[Dict]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, CD, Dict, IntDD[Dict], IntDD[CD]]",
         context: Type[CCT],
         chat_data: Type[CD],
     ):
@@ -126,15 +130,15 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, BD, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, Dict, BD, IntDD[Dict], IntDD[Dict]]",
         context: Type[CCT],
-        user_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, Dict, Dict, UDM, IntDD[Dict]]",
         context: Type[CCT],
         chat_data_mapping: Type[UDM],
     ):
@@ -142,7 +146,7 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, Dict, Dict, Dict, IntDD[Dict], CDM]",
         context: Type[CCT],
         user_data_mapping: Type[CDM],
     ):
@@ -150,47 +154,53 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, dict, defaultdict, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, "
+        "IntDD[UD], IntDD[CD]]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, BD, defaultdict, defaultdict]",
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, "
+        "IntDD[UD], IntDD[Dict]]",
+        bot_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, dict, UDM, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
+        "UDM, IntDD[Dict]]",
+        bot_data: Type[BD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, dict, defaultdict, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
+        "IntDD[UD], CDM]",
+        bot_data: Type[BD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, BD, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, "
+        "IntDD[Dict], IntDD[CD]]",
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
+        "UDM, IntDD[CD]]",
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
     ):
@@ -198,7 +208,8 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
+        "IntDD[Dict], CDM]",
         chat_data: Type[CD],
         user_data_mapping: Type[CDM],
     ):
@@ -206,23 +217,25 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, BD, UDM, defaultdict]",
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, UDM, "
+        "IntDD[Dict]]",
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, BD, defaultdict, CDM]",
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, "
+        "IntDD[Dict], CDM]",
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, dict, UDM, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, UDM, CDM]",
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -230,52 +243,52 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, dict, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, CD, Dict, IntDD[UD], IntDD[CD]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, BD, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, Dict, BD, IntDD[UD], IntDD[Dict]]",
         context: Type[CCT],
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        bot_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, Dict, Dict, UDM, IntDD[Dict]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, UD, Dict, Dict, IntDD[UD], CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, BD, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, CD, BD, IntDD[Dict], IntDD[CD]]",
         context: Type[CCT],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, CD, Dict, UDM, IntDD[CD]]",
         context: Type[CCT],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
@@ -284,7 +297,7 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, Dict, CD, Dict, IntDD[Dict], CDM]",
         context: Type[CCT],
         chat_data: Type[CD],
         user_data_mapping: Type[CDM],
@@ -293,25 +306,25 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, BD, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, Dict, BD, UDM, IntDD[Dict]]",
         context: Type[CCT],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, BD, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, Dict, Dict, BD, IntDD[Dict], CDM]",
         context: Type[CCT],
-        user_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, dict, UDM, CDM]",
+        self: "ContextCustomizer[CCT, Dict, Dict, Dict, UDM, CDM]",
         context: Type[CCT],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
@@ -320,17 +333,17 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, BD, defaultdict, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, IntDD[UD], IntDD[CD]]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, dict, UDM, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, UDM, IntDD[CD]]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
     ):
@@ -338,8 +351,8 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, dict, defaultdict, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, IntDD[UD], CDM]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
         user_data_mapping: Type[CDM],
     ):
@@ -347,26 +360,26 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, BD, UDM, defaultdict]",
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, UDM, IntDD[Dict]]",
+        bot_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, BD, defaultdict, CDM]",
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, IntDD[UD], CDM]",
+        bot_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, dict, UDM, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, UDM, CDM]",
+        bot_data: Type[BD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -374,25 +387,25 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, BD, UDM, defaultdict]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, UDM, IntDD[CD]]",
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, BD, defaultdict, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, IntDD[Dict], CDM]",
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, dict, UDM, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, UDM, CDM]",
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
@@ -401,8 +414,8 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, dict, BD, UDM, CDM]",
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, UDM, CDM]",
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -410,19 +423,19 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, defaultdict, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, CD, BD, IntDD[UD], IntDD[CD]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, dict, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, CD, Dict, UDM, IntDD[CD]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
     ):
@@ -430,9 +443,9 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, dict, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, UD, CD, Dict, IntDD[UD], CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
         user_data_mapping: Type[CDM],
     ):
@@ -440,29 +453,29 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, BD, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, Dict, BD, UDM, IntDD[Dict]]",
         context: Type[CCT],
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        bot_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, BD, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, UD, Dict, BD, IntDD[UD], CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        bot_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, dict, UDM, CDM]",
+        self: "ContextCustomizer[CCT, UD, Dict, Dict, UDM, CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -470,27 +483,27 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, BD, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, Dict, CD, BD, UDM, IntDD[CD]]",
         context: Type[CCT],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, BD, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, Dict, CD, BD, IntDD[Dict], CDM]",
         context: Type[CCT],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, dict, UDM, CDM]",
+        self: "ContextCustomizer[CCT, Dict, CD, Dict, UDM, CDM]",
         context: Type[CCT],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
@@ -500,9 +513,9 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, dict, BD, UDM, CDM]",
+        self: "ContextCustomizer[CCT, Dict, Dict, BD, UDM, CDM]",
         context: Type[CCT],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -510,28 +523,28 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, BD, UDM, defaultdict]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, UDM, IntDD[CD]]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, BD, defaultdict, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, IntDD[UD], CDM]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, dict, UDM, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, UDM, CDM]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
@@ -540,9 +553,9 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, dict, BD, UDM, CDM]",
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, UDM, CDM]",
+        bot_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -550,9 +563,9 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, dict, CD, BD, UDM, CDM]",
+        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, UDM, CDM]",
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -560,31 +573,31 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, defaultdict]",
+        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, IntDD[CD]]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, defaultdict, CDM]",
+        self: "ContextCustomizer[CCT, UD, CD, BD, IntDD[UD], CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         user_data_mapping: Type[CDM],
     ):
         ...
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, dict, UDM, CDM]",
+        self: "ContextCustomizer[CCT, UD, CD, Dict, UDM, CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
+        bot_data: Type[BD],
         chat_data: Type[CD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
@@ -593,10 +606,10 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, UD, dict, BD, UDM, CDM]",
+        self: "ContextCustomizer[CCT, UD, Dict, BD, UDM, CDM]",
         context: Type[CCT],
-        bot_data: Type[UD],
-        user_data: Type[BD],
+        bot_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -604,10 +617,10 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CCT, dict, CD, BD, UDM, CDM]",
+        self: "ContextCustomizer[CCT, Dict, CD, BD, UDM, CDM]",
         context: Type[CCT],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -615,10 +628,10 @@ def __init__(
 
     @overload
     def __init__(
-        self: "ContextCustomizer[CallbackContext, UD, CD, BD, UDM, CDM]",
-        bot_data: Type[UD],
+        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, UDM, CDM]",
+        bot_data: Type[BD],
         chat_data: Type[CD],
-        user_data: Type[BD],
+        user_data: Type[UD],
         chat_data_mapping: Type[UDM],
         user_data_mapping: Type[CDM],
     ):
@@ -648,7 +661,7 @@ def __init__(  # type: ignore[no-untyped-def]
         self._user_data_mapping = user_data_mapping
 
     @property
-    def context(self) -> Optional[Type]:
+    def context(self) -> Type[CCT]:
         return self._context
 
     @context.setter
@@ -656,7 +669,7 @@ def context(self, value: Any) -> NoReturn:
         raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
 
     @property
-    def bot_data(self) -> Optional[Type]:
+    def bot_data(self) -> Type[BD]:
         return self._bot_data
 
     @bot_data.setter
@@ -664,7 +677,7 @@ def bot_data(self, value: Any) -> NoReturn:
         raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
 
     @property
-    def chat_data(self) -> Optional[Type]:
+    def chat_data(self) -> Type[CD]:
         return self._chat_data
 
     @chat_data.setter
@@ -672,7 +685,7 @@ def chat_data(self, value: Any) -> NoReturn:
         raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
 
     @property
-    def user_data(self) -> Optional[Type]:
+    def user_data(self) -> Type[UD]:
         return self._user_data
 
     @user_data.setter
@@ -680,7 +693,7 @@ def user_data(self, value: Any) -> NoReturn:
         raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
 
     @property
-    def user_data_mapping(self) -> Optional[Type]:
+    def user_data_mapping(self) -> Type[UDM]:
         return self._user_data_mapping
 
     @user_data_mapping.setter
@@ -688,7 +701,7 @@ def user_data_mapping(self, value: Any) -> NoReturn:
         raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
 
     @property
-    def chat_data_mapping(self) -> Optional[Type]:
+    def chat_data_mapping(self) -> Type[CDM]:
         return self._chat_data_mapping
 
     @chat_data_mapping.setter
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index 5c9c76c04ed..4effde2a989 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -47,10 +47,9 @@
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
-from telegram.utils.types import CCT, UD, CD, BD, UDM, CDM
+from telegram.utils.types import CCT, UD, CD, BD, UDM, CDM, IntDD  # pylint: disable=W0611
 
 if TYPE_CHECKING:
-    from collections import defaultdict
     from telegram import Bot
     from telegram.ext import JobQueue
 
@@ -162,7 +161,8 @@ class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     @overload
     def __init__(
-        self: 'Dispatcher[CallbackContext, dict, dict, dict, defaultdict, defaultdict]',
+        self: 'Dispatcher[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, '
+        'IntDD[Dict], IntDD[Dict]]',
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
@@ -189,7 +189,7 @@ def __init__(
     ):
         ...
 
-    def __init__(  # type: ignore[no-untyped-def]
+    def __init__(
         self,
         bot: 'Bot',
         update_queue: Queue,
@@ -198,7 +198,9 @@ def __init__(  # type: ignore[no-untyped-def]
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer=ContextCustomizer(),
+        context_customizer: ContextCustomizer[
+            CCT, UD, CD, BD, UDM, CDM
+        ] = ContextCustomizer(),  # type: ignore[assignment]
     ):
         self.bot = bot
         self.update_queue = update_queue
@@ -214,10 +216,10 @@ def __init__(  # type: ignore[no-untyped-def]
                 stacklevel=3,
             )
 
-        self.user_data = self.context_customizer.user_data_mapping(
+        self.user_data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
             self.context_customizer.user_data
         )
-        self.chat_data = self.context_customizer.chat_data_mapping(
+        self.chat_data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
             self.context_customizer.chat_data
         )
         self.bot_data = self.context_customizer.bot_data()
@@ -229,14 +231,14 @@ def __init__(  # type: ignore[no-untyped-def]
             self.persistence = persistence
             self.persistence.set_bot(self.bot)
             if self.persistence.store_user_data:
-                self.user_data = self.persistence.get_user_data()
+                self.user_data = self.persistence.get_user_data()  # type: ignore[assignment]
                 if not isinstance(self.user_data, self.context_customizer.user_data_mapping):
                     raise ValueError(
                         f"user_data must be of type "
                         f"{self.context_customizer.user_data_mapping.__name__}"
                     )
             if self.persistence.store_chat_data:
-                self.chat_data = self.persistence.get_chat_data()
+                self.chat_data = self.persistence.get_chat_data()  # type: ignore[assignment]
                 if not isinstance(self.chat_data, self.context_customizer.chat_data_mapping):
                     raise ValueError(
                         f"chat_data must be of type "
diff --git a/telegram/utils/types.py b/telegram/utils/types.py
index 7dd31211889..4ca70feb12d 100644
--- a/telegram/utils/types.py
+++ b/telegram/utils/types.py
@@ -29,6 +29,7 @@
     TypeVar,
     Union,
     Mapping,
+    DefaultDict,
 )
 
 if TYPE_CHECKING:
@@ -65,3 +66,7 @@
 """Type of the user data mapping."""
 CDM = TypeVar('CDM', bound=Mapping)
 """Type of the chat data mapping."""
+
+DDType = TypeVar('DDType')
+IntDD = DefaultDict[int, DDType]
+"""Type for default dicts with integer keys and generic value."""

From f24cdff56d3c0683f4f03e95d4677f2d858f0965 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sat, 16 Jan 2021 17:10:00 +0100
Subject: [PATCH 07/31] Test Dispatcher integration

---
 examples/echobot.py               |  2 +-
 telegram/ext/basepersistence.py   |  3 +-
 telegram/ext/contextcustomizer.py | 12 +++++++
 telegram/ext/updater.py           |  6 ++--
 tests/test_dispatcher.py          | 54 +++++++++++++++++++++++++++----
 tests/test_jobqueue.py            | 15 +++++++--
 6 files changed, 77 insertions(+), 15 deletions(-)

diff --git a/examples/echobot.py b/examples/echobot.py
index bb9ceb855bd..c8a264584bd 100644
--- a/examples/echobot.py
+++ b/examples/echobot.py
@@ -42,7 +42,7 @@ def help_command(update: Update, context: CallbackContext) -> None:
     update.message.reply_text('Help!')
 
 
-def echo(update: str, context: CallbackContext) -> None:
+def echo(update: Update, context: CallbackContext) -> None:
     """Echo the user message."""
     update.message.reply_text(update.message.text)
 
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 5a60994f805..ec52fd9ced0 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -19,9 +19,8 @@
 """This module contains the BasePersistence class."""
 import warnings
 from abc import ABC, abstractmethod
-from collections.abc import Mapping
 from copy import copy
-from typing import Any, Dict, Optional, Tuple, cast, ClassVar, Generic
+from typing import Any, Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping
 
 from telegram import Bot
 
diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
index 98c5e771092..961d32706aa 100644
--- a/telegram/ext/contextcustomizer.py
+++ b/telegram/ext/contextcustomizer.py
@@ -637,6 +637,18 @@ def __init__(
     ):
         ...
 
+    @overload
+    def __init__(
+        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, CDM]",
+        context: Type[CCT],
+        bot_data: Type[BD],
+        chat_data: Type[CD],
+        user_data: Type[UD],
+        chat_data_mapping: Type[UDM],
+        user_data_mapping: Type[CDM],
+    ):
+        ...
+
     def __init__(  # type: ignore[no-untyped-def]
         self,
         context=CallbackContext,
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 65d3f93923b..62186530f54 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -136,7 +136,7 @@ def __init__(
         private_key_password: bytes = None,
         user_sig_handler: Callable = None,
         request_kwargs: Dict[str, Any] = None,
-        persistence: BasePersistence = None,  # pylint: disable=E0601
+        persistence: 'BasePersistence' = None,  # pylint: disable=E0601
         defaults: 'Defaults' = None,
         use_context: bool = True,
         base_file_url: str = None,
@@ -154,7 +154,7 @@ def __init__(
         private_key_password: bytes = None,
         user_sig_handler: Callable = None,
         request_kwargs: Dict[str, Any] = None,
-        persistence: BasePersistence = None,
+        persistence: 'BasePersistence' = None,
         defaults: 'Defaults' = None,
         use_context: bool = True,
         base_file_url: str = None,
@@ -180,7 +180,7 @@ def __init__(  # type: ignore[no-untyped-def,misc]
         private_key_password: bytes = None,
         user_sig_handler: Callable = None,
         request_kwargs: Dict[str, Any] = None,
-        persistence: BasePersistence = None,
+        persistence: 'BasePersistence' = None,
         defaults: 'Defaults' = None,
         use_context: bool = True,
         dispatcher=None,
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 4fb4007300c..4c001b11c5b 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -904,29 +904,71 @@ def dummy_callback(*args, **kwargs):
         finally:
             dp.bot.defaults = None
 
+    def test_custom_context_init(self, bot):
+        class CustomUserMapping(defaultdict):
+            pass
+
+        class CustomChatMapping(defaultdict):
+            pass
+
+        cc = ContextCustomizer(
+            context=CustomContext,
+            user_data=int,
+            chat_data=float,
+            bot_data=complex,
+            user_data_mapping=CustomUserMapping,
+            chat_data_mapping=CustomChatMapping,
+        )
+
+        dispatcher = Dispatcher(bot, Queue(), context_customizer=cc)
+
+        assert isinstance(dispatcher.user_data, CustomUserMapping)
+        assert isinstance(dispatcher.user_data[1], int)
+        assert isinstance(dispatcher.chat_data, CustomChatMapping)
+        assert isinstance(dispatcher.chat_data[1], float)
+        assert isinstance(dispatcher.bot_data, complex)
+
     def test_custom_context_error_handler(self, bot):
         def error_handler(_, context):
-            self.received = type(context)
+            self.received = (
+                type(context),
+                type(context.user_data),
+                type(context.chat_data),
+                type(context.bot_data),
+            )
 
         dispatcher = Dispatcher(
-            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+            bot,
+            Queue(),
+            context_customizer=ContextCustomizer(
+                context=CustomContext, bot_data=int, user_data=float, chat_data=complex
+            ),
         )
         dispatcher.add_error_handler(error_handler)
         dispatcher.add_handler(MessageHandler(Filters.all, self.callback_raise_error))
 
         dispatcher.process_update(self.message_update)
         sleep(0.1)
-        assert self.received == CustomContext
+        assert self.received == (CustomContext, float, complex, int)
 
     def test_custom_context_handler_callback(self, bot):
         def callback(_, context):
-            self.received = type(context)
+            self.received = (
+                type(context),
+                type(context.user_data),
+                type(context.chat_data),
+                type(context.bot_data),
+            )
 
         dispatcher = Dispatcher(
-            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+            bot,
+            Queue(),
+            context_customizer=ContextCustomizer(
+                context=CustomContext, bot_data=int, user_data=float, chat_data=complex
+            ),
         )
         dispatcher.add_handler(MessageHandler(Filters.all, callback))
 
         dispatcher.process_update(self.message_update)
         sleep(0.1)
-        assert self.received == CustomContext
+        assert self.received == (CustomContext, float, complex, int)
diff --git a/tests/test_jobqueue.py b/tests/test_jobqueue.py
index 3813db16777..a665672c208 100644
--- a/tests/test_jobqueue.py
+++ b/tests/test_jobqueue.py
@@ -518,13 +518,22 @@ def test_dispatch_error_that_raises_errors(self, job_queue, dp, caplog):
 
     def test_custom_context(self, bot, job_queue):
         dispatcher = Dispatcher(
-            bot, Queue(), context_customizer=ContextCustomizer(context=CustomContext)
+            bot,
+            Queue(),
+            context_customizer=ContextCustomizer(
+                context=CustomContext, bot_data=int, user_data=float, chat_data=complex
+            ),
         )
         job_queue.set_dispatcher(dispatcher)
 
         def callback(context):
-            self.result = type(context)
+            self.result = (
+                type(context),
+                context.user_data,
+                context.chat_data,
+                type(context.bot_data),
+            )
 
         job_queue.run_once(callback, 0.1)
         sleep(0.15)
-        assert self.result == CustomContext
+        assert self.result == (CustomContext, None, None, int)

From c2219445e47fd4c1e685e39970c21830a43631bf Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 17 Jan 2021 22:20:35 +0100
Subject: [PATCH 08/31] Pass CC to PP

---
 .../source/telegram.ext.contextcustomizer.rst |   5 +-
 telegram/ext/basepersistence.py               |   2 +-
 telegram/ext/contextcustomizer.py             |  24 +--
 telegram/ext/dispatcher.py                    |  13 +-
 telegram/ext/handler.py                       |   4 +-
 telegram/ext/picklepersistence.py             | 138 ++++++++++++++----
 telegram/ext/updater.py                       |  31 ++--
 7 files changed, 147 insertions(+), 70 deletions(-)

diff --git a/docs/source/telegram.ext.contextcustomizer.rst b/docs/source/telegram.ext.contextcustomizer.rst
index 505c2c0c1c7..c08954f2d05 100644
--- a/docs/source/telegram.ext.contextcustomizer.rst
+++ b/docs/source/telegram.ext.contextcustomizer.rst
@@ -1,6 +1,9 @@
 telegram.ext.ContextCustomizer
 ==============================
 
-.. autoclass:: telegram.ext.ContextCustomizer
+..
+    We manually set the signature here in order to not display all the overload variants
+
+.. autoclass:: telegram.ext.ContextCustomizer(context: Type[CCT], bot_data: Type[BD], chat_data: Type[CD], user_data: Type[UD], chat_data_mapping: Type[UDM], user_data_mapping: Type[CDM])
     :members:
     :show-inheritance:
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index ec52fd9ced0..1ceaf58599e 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -27,7 +27,7 @@
 from telegram.utils.types import ConversationDict, CD, UD, BD, UDM, CDM
 
 
-class BasePersistence(ABC, Generic[UD, CD, BD, UDM, CDM]):
+class BasePersistence(Generic[UD, CD, BD, UDM, CDM], ABC):
     """Interface class for adding persistence to your bot.
     Subclass this object for different implementations of a persistent bot.
 
diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
index 961d32706aa..880a75e2f89 100644
--- a/telegram/ext/contextcustomizer.py
+++ b/telegram/ext/contextcustomizer.py
@@ -35,27 +35,33 @@ class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
             (error-)handler callbacks and job callbacks. Must be a subclass of
             :class:`telegram.ext.CallbackContext`. Defaults to
             :class:`telegram.ext.CallbackContext`.
-        bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`. Must support
-            instantiating without arguments
-        chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`.
-        user_data (:obj:`type`, optional): Determines the type of ``context.user_data` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`Dict`.
+        bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            instantiating without arguments.
+        chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+        user_data (:obj:`type`, optional): Determines the type of ``context.user_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
         chat_data_mapping (:obj:`type`, optional): In combination with :attr:`chat_data` determines
-            the type of :attr:`telegram.ext.Dispatcher.chat_data`. Must support instantiating via
+            the type of :attr:`telegram.ext.Dispatcher.chat_data`. Must be a subclass of
+            :obj:`collections.abc.Mapping` with integer keys supporting instantiating via
 
             .. code:: python
 
                 chat_data_mapping(chat_data)
 
+            Defaults to :obj:`defaultdict`.
+
         user_data_mapping (:obj:`type`, optional): In combination with :attr:`user_data` determines
-            the type of :attr:`telegram.ext.Dispatcher.user_data`. Must support instantiating via
+            the type of :attr:`telegram.ext.Dispatcher.user_data`. Must be a subclass of
+            :obj:`collections.abc.Mapping` with integer keys supporting instantiating via
 
             .. code:: python
 
                 user_data_mapping(user_data)
 
+            Defaults to :obj:`defaultdict`.
+
     """
 
     @overload
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index 4effde2a989..91feefc1200 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -37,6 +37,7 @@
     Generic,
     TypeVar,
     overload,
+    cast,
 )
 from uuid import uuid4
 
@@ -183,9 +184,7 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextCustomizer[
-            CCT, UD, CD, BD, UDM, CDM
-        ] = ContextCustomizer(),  # type: ignore[assignment]
+        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
     ):
         ...
 
@@ -198,16 +197,16 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextCustomizer[
-            CCT, UD, CD, BD, UDM, CDM
-        ] = ContextCustomizer(),  # type: ignore[assignment]
+        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
     ):
         self.bot = bot
         self.update_queue = update_queue
         self.job_queue = job_queue
         self.workers = workers
         self.use_context = use_context
-        self.context_customizer = context_customizer
+        self.context_customizer = cast(
+            ContextCustomizer[CCT, UD, CD, BD, UDM, CDM], context_customizer or ContextCustomizer()
+        )
 
         if not use_context:
             warnings.warn(
diff --git a/telegram/ext/handler.py b/telegram/ext/handler.py
index 5764ebaad2b..10238cbadea 100644
--- a/telegram/ext/handler.py
+++ b/telegram/ext/handler.py
@@ -211,9 +211,9 @@ def collect_optional_args(
             optional_args['job_queue'] = dispatcher.job_queue
         if self.pass_user_data and isinstance(update, Update):
             user = update.effective_user
-            optional_args['user_data'] = dispatcher.user_data[user.id if user else None]
+            optional_args['user_data'] = dispatcher.user_data[user.id] if user else None
         if self.pass_chat_data and isinstance(update, Update):
             chat = update.effective_chat
-            optional_args['chat_data'] = dispatcher.chat_data[chat.id if chat else None]
+            optional_args['chat_data'] = dispatcher.chat_data[chat.id] if chat else None
 
         return optional_args
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index df6e7598ff4..36092e9a0b9 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -18,15 +18,17 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains the PicklePersistence class."""
 import pickle
-from collections import defaultdict
-from copy import deepcopy
-from typing import Any, DefaultDict, Dict, Optional, Tuple
+from typing import Any, Dict, Optional, Tuple, overload, Mapping, cast, TypeVar, MutableMapping
 
 from telegram.ext import BasePersistence
-from telegram.utils.types import ConversationDict
+from telegram.utils.types import ConversationDict, CD, UD, BD, IntDD  # pylint: disable=W0611
+from .contextcustomizer import ContextCustomizer
 
+UDM = TypeVar('UDM', bound=MutableMapping)
+CDM = TypeVar('CDM', bound=MutableMapping)
 
-class PicklePersistence(BasePersistence):
+
+class PicklePersistence(BasePersistence[UD, CD, BD, UDM, CDM]):
     """Using python's builtin pickle for making you bot persistent.
 
     Warning:
@@ -54,6 +56,23 @@ class PicklePersistence(BasePersistence):
             :meth:`flush` is called and keep data in memory until that happens. When
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
+        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
+            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+            ``context`` interface.
+
+            Note:
+                The types for :attr:`telegram.ext.ContextCustomizer.user_data_mapping` and
+                :attr:`telegram.ext.ContextCustomizer.chat_data_mapping` must be subclasses of
+                :class:`collections.abc.MutableMapping` and support instantiation via
+
+                .. code:: python
+
+                    chat/user_data_mapping(chat/user_data_type[, data])
+
+                where ``data`` is of type ``chat/user_data_mapping``.
+
+            If not passed, the defaults documented in
+            :class:`telegram.ext.ContextCustomizer` will be used.
 
     Attributes:
         filename (:obj:`str`): The filename for storing the pickle files. When :attr:`single_file`
@@ -71,8 +90,35 @@ class PicklePersistence(BasePersistence):
             :meth:`flush` is called and keep data in memory until that happens. When
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
+        context_customizer (:class:`telegram.ext.ContextCustomizer`): Container for the types used
+            in the ``context`` interface.
     """
 
+    @overload
+    def __init__(
+        self: 'PicklePersistence[Dict, Dict, Dict, IntDD[Dict], IntDD[Dict]]',
+        filename: str,
+        store_user_data: bool = True,
+        store_chat_data: bool = True,
+        store_bot_data: bool = True,
+        single_file: bool = True,
+        on_flush: bool = False,
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'PicklePersistence[UD, CD, BD, UDM, CDM]',
+        filename: str,
+        store_user_data: bool = True,
+        store_chat_data: bool = True,
+        store_bot_data: bool = True,
+        single_file: bool = True,
+        on_flush: bool = False,
+        context_customizer: ContextCustomizer[Any, UD, CD, BD, UDM, CDM] = None,
+    ):
+        ...
+
     def __init__(
         self,
         filename: str,
@@ -81,6 +127,7 @@ def __init__(
         store_bot_data: bool = True,
         single_file: bool = True,
         on_flush: bool = False,
+        context_customizer: ContextCustomizer[Any, UD, CD, BD, UDM, CDM] = None,
     ):
         super().__init__(
             store_user_data=store_user_data,
@@ -90,26 +137,41 @@ def __init__(
         self.filename = filename
         self.single_file = single_file
         self.on_flush = on_flush
-        self.user_data: Optional[DefaultDict[int, Dict]] = None
-        self.chat_data: Optional[DefaultDict[int, Dict]] = None
-        self.bot_data: Optional[Dict] = None
+        self.user_data: Optional[MutableMapping[int, UD]] = None
+        self.chat_data: Optional[MutableMapping[int, CD]] = None
+        self.bot_data: Optional[BD] = None
         self.conversations: Optional[Dict[str, Dict[Tuple, Any]]] = None
+        self.context_customizer = cast(
+            ContextCustomizer[Any, UD, CD, BD, UDM, CDM], context_customizer or ContextCustomizer()
+        )
 
     def load_singlefile(self) -> None:
         try:
             filename = self.filename
             with open(self.filename, "rb") as file:
                 data = pickle.load(file)
-                self.user_data = defaultdict(dict, data['user_data'])
-                self.chat_data = defaultdict(dict, data['chat_data'])
+                self.user_data = (
+                    self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
+                        self.context_customizer.user_data, data['user_data']
+                    )
+                )
+                self.chat_data = (
+                    self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
+                        self.context_customizer.chat_data, data['chat_data']
+                    )
+                )
                 # For backwards compatibility with files not containing bot data
                 self.bot_data = data.get('bot_data', {})
                 self.conversations = data['conversations']
         except IOError:
             self.conversations = dict()
-            self.user_data = defaultdict(dict)
-            self.chat_data = defaultdict(dict)
-            self.bot_data = {}
+            self.user_data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
+                self.context_customizer.user_data
+            )
+            self.chat_data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
+                self.context_customizer.chat_data
+            )
+            self.bot_data = self.context_customizer.bot_data()
         except pickle.UnpicklingError as exc:
             raise TypeError(f"File {filename} does not contain valid pickle data") from exc
         except Exception as exc:
@@ -142,7 +204,7 @@ def dump_file(filename: str, data: Any) -> None:
         with open(filename, "wb") as file:
             pickle.dump(data, file)
 
-    def get_user_data(self) -> DefaultDict[int, Dict[Any, Any]]:
+    def get_user_data(self) -> Mapping[int, UD]:
         """Returns the user_data from the pickle file if it exists or an empty :obj:`defaultdict`.
 
         Returns:
@@ -154,15 +216,19 @@ def get_user_data(self) -> DefaultDict[int, Dict[Any, Any]]:
             filename = f"{self.filename}_user_data"
             data = self.load_file(filename)
             if not data:
-                data = defaultdict(dict)
+                data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.user_data
+                )
             else:
-                data = defaultdict(dict, data)
+                data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.user_data, data
+                )
             self.user_data = data
         else:
             self.load_singlefile()
-        return deepcopy(self.user_data)  # type: ignore[arg-type]
+        return self.user_data  # type: ignore[return-value]
 
-    def get_chat_data(self) -> DefaultDict[int, Dict[Any, Any]]:
+    def get_chat_data(self) -> Mapping[int, CD]:
         """Returns the chat_data from the pickle file if it exists or an empty :obj:`defaultdict`.
 
         Returns:
@@ -174,15 +240,19 @@ def get_chat_data(self) -> DefaultDict[int, Dict[Any, Any]]:
             filename = f"{self.filename}_chat_data"
             data = self.load_file(filename)
             if not data:
-                data = defaultdict(dict)
+                data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.chat_data
+                )
             else:
-                data = defaultdict(dict, data)
+                data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.chat_data, data
+                )
             self.chat_data = data
         else:
             self.load_singlefile()
-        return deepcopy(self.chat_data)  # type: ignore[arg-type]
+        return self.chat_data  # type: ignore[return-value]
 
-    def get_bot_data(self) -> Dict[Any, Any]:
+    def get_bot_data(self) -> BD:
         """Returns the bot_data from the pickle file if it exists or an empty :obj:`dict`.
 
         Returns:
@@ -198,7 +268,7 @@ def get_bot_data(self) -> Dict[Any, Any]:
             self.bot_data = data
         else:
             self.load_singlefile()
-        return deepcopy(self.bot_data)  # type: ignore[arg-type]
+        return self.bot_data  # type: ignore[return-value]
 
     def get_conversations(self, name: str) -> ConversationDict:
         """Returns the conversations from the pickle file if it exsists or an empty dict.
@@ -244,7 +314,7 @@ def update_conversation(
             else:
                 self.dump_singlefile()
 
-    def update_user_data(self, user_id: int, data: Dict) -> None:
+    def update_user_data(self, user_id: int, data: UD) -> None:
         """Will update the user_data and depending on :attr:`on_flush` save the pickle file.
 
         Args:
@@ -252,7 +322,12 @@ def update_user_data(self, user_id: int, data: Dict) -> None:
             data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
         """
         if self.user_data is None:
-            self.user_data = defaultdict(dict)
+            self.user_data = cast(
+                MutableMapping[int, UD],
+                self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.user_data
+                ),
+            )
         if self.user_data.get(user_id) == data:
             return
         self.user_data[user_id] = data
@@ -263,7 +338,7 @@ def update_user_data(self, user_id: int, data: Dict) -> None:
             else:
                 self.dump_singlefile()
 
-    def update_chat_data(self, chat_id: int, data: Dict) -> None:
+    def update_chat_data(self, chat_id: int, data: CD) -> None:
         """Will update the chat_data and depending on :attr:`on_flush` save the pickle file.
 
         Args:
@@ -271,7 +346,12 @@ def update_chat_data(self, chat_id: int, data: Dict) -> None:
             data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
         """
         if self.chat_data is None:
-            self.chat_data = defaultdict(dict)
+            self.chat_data = cast(
+                MutableMapping[int, CD],
+                self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
+                    self.context_customizer.chat_data
+                ),
+            )
         if self.chat_data.get(chat_id) == data:
             return
         self.chat_data[chat_id] = data
@@ -282,7 +362,7 @@ def update_chat_data(self, chat_id: int, data: Dict) -> None:
             else:
                 self.dump_singlefile()
 
-    def update_bot_data(self, data: Dict) -> None:
+    def update_bot_data(self, data: BD) -> None:
         """Will update the bot_data and depending on :attr:`on_flush` save the pickle file.
 
         Args:
@@ -290,7 +370,7 @@ def update_bot_data(self, data: Dict) -> None:
         """
         if self.bot_data == data:
             return
-        self.bot_data = data.copy()
+        self.bot_data = data
         if not self.on_flush:
             if not self.single_file:
                 filename = f"{self.filename}_bot_data"
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 62186530f54..7547a6fa08e 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -252,27 +252,16 @@ def __init__(  # type: ignore[no-untyped-def,misc]
             self.job_queue = JobQueue()
             self.__exception_event = Event()
             self.persistence = persistence
-            if context_customizer:
-                self.dispatcher = Dispatcher(
-                    self.bot,
-                    self.update_queue,
-                    job_queue=self.job_queue,
-                    workers=workers,
-                    exception_event=self.__exception_event,
-                    persistence=persistence,
-                    use_context=use_context,
-                    context_customizer=context_customizer,
-                )
-            else:
-                self.dispatcher = Dispatcher(  # type: ignore[assignment]
-                    self.bot,
-                    self.update_queue,
-                    job_queue=self.job_queue,
-                    workers=workers,
-                    exception_event=self.__exception_event,
-                    persistence=persistence,
-                    use_context=use_context,
-                )
+            self.dispatcher = Dispatcher(
+                self.bot,
+                self.update_queue,
+                job_queue=self.job_queue,
+                workers=workers,
+                exception_event=self.__exception_event,
+                persistence=persistence,
+                use_context=use_context,
+                context_customizer=context_customizer,
+            )
             self.job_queue.set_dispatcher(self.dispatcher)
         else:
             con_pool_size = dispatcher.workers + 4

From 6eed0ea3fdac55c51247db5bc2b1b0d67079ff16 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 21 Jan 2021 20:21:25 +0100
Subject: [PATCH 09/31] Fix tests

---
 telegram/ext/handler.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/telegram/ext/handler.py b/telegram/ext/handler.py
index 10238cbadea..5764ebaad2b 100644
--- a/telegram/ext/handler.py
+++ b/telegram/ext/handler.py
@@ -211,9 +211,9 @@ def collect_optional_args(
             optional_args['job_queue'] = dispatcher.job_queue
         if self.pass_user_data and isinstance(update, Update):
             user = update.effective_user
-            optional_args['user_data'] = dispatcher.user_data[user.id] if user else None
+            optional_args['user_data'] = dispatcher.user_data[user.id if user else None]
         if self.pass_chat_data and isinstance(update, Update):
             chat = update.effective_chat
-            optional_args['chat_data'] = dispatcher.chat_data[chat.id] if chat else None
+            optional_args['chat_data'] = dispatcher.chat_data[chat.id if chat else None]
 
         return optional_args

From c93eb28eb464bb958dd7d78f33ec24b89886b238 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 21 Jan 2021 21:33:59 +0100
Subject: [PATCH 10/31] Add tests for PicklePersistence

---
 telegram/ext/picklepersistence.py |  4 +--
 tests/test_persistence.py         | 52 ++++++++++++++++++++++++++++++-
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index 4b6ec9c70a3..a66d03d1f1e 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -161,7 +161,7 @@ def load_singlefile(self) -> None:
                     )
                 )
                 # For backwards compatibility with files not containing bot data
-                self.bot_data = data.get('bot_data', {})
+                self.bot_data = data.get('bot_data', self.context_customizer.bot_data())
                 self.conversations = data['conversations']
         except OSError:
             self.conversations = dict()
@@ -264,7 +264,7 @@ def get_bot_data(self) -> BD:
             filename = f"{self.filename}_bot_data"
             data = self.load_file(filename)
             if not data:
-                data = {}
+                data = self.context_customizer.bot_data()
             self.bot_data = data
         else:
             self.load_singlefile()
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index 2d59216a2f9..48f88affd07 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -45,6 +45,7 @@
     DictPersistence,
     TypeHandler,
     JobQueue,
+    ContextCustomizer,
 )
 
 
@@ -775,7 +776,11 @@ def update(bot):
     return Update(0, message=message)
 
 
-class TestPickelPersistence:
+class CustomMapping(defaultdict):
+    pass
+
+
+class TestPicklePersistence:
     def test_no_files_present_multi_file(self, pickle_persistence):
         assert pickle_persistence.get_user_data() == defaultdict(dict)
         assert pickle_persistence.get_user_data() == defaultdict(dict)
@@ -1364,6 +1369,51 @@ def job_callback(context):
         user_data = pickle_persistence.get_user_data()
         assert user_data[789] == {'test3': '123'}
 
+    @pytest.mark.parametrize('singlefile', [True, False])
+    @pytest.mark.parametrize('udm', [defaultdict, CustomMapping])
+    @pytest.mark.parametrize('cdm', [defaultdict, CustomMapping])
+    @pytest.mark.parametrize('ud', [int, float, complex])
+    @pytest.mark.parametrize('cd', [int, float, complex])
+    @pytest.mark.parametrize('bd', [int, float, complex])
+    def test_with_context_customizer(self, ud, cd, bd, udm, cdm, singlefile):
+        cc = ContextCustomizer(
+            user_data=ud, chat_data=cd, bot_data=bd, user_data_mapping=udm, chat_data_mapping=cdm
+        )
+        persistence = PicklePersistence(
+            'pickletest', single_file=singlefile, context_customizer=cc
+        )
+
+        assert isinstance(persistence.get_user_data(), udm)
+        assert isinstance(persistence.get_user_data()[1], ud)
+        assert persistence.get_user_data()[1] == 0
+        assert isinstance(persistence.get_chat_data(), cdm)
+        assert isinstance(persistence.get_chat_data()[1], cd)
+        assert persistence.get_chat_data()[1] == 0
+        assert isinstance(persistence.get_bot_data(), bd)
+        assert persistence.get_bot_data() == 0
+
+        persistence.user_data = None
+        persistence.chat_data = None
+        persistence.update_user_data(1, ud(1))
+        persistence.update_chat_data(1, cd(1))
+        persistence.update_bot_data(bd(1))
+        assert persistence.get_user_data()[1] == 1
+        assert persistence.get_chat_data()[1] == 1
+        assert persistence.get_bot_data() == 1
+
+        persistence.flush()
+        persistence = PicklePersistence(
+            'pickletest', single_file=singlefile, context_customizer=cc
+        )
+        assert isinstance(persistence.get_user_data(), udm)
+        assert isinstance(persistence.get_user_data()[1], ud)
+        assert persistence.get_user_data()[1] == 1
+        assert isinstance(persistence.get_chat_data(), cdm)
+        assert isinstance(persistence.get_chat_data()[1], cd)
+        assert persistence.get_chat_data()[1] == 1
+        assert isinstance(persistence.get_bot_data(), bd)
+        assert persistence.get_bot_data() == 1
+
 
 @pytest.fixture(scope='function')
 def user_data_json(user_data):

From c72559fabc42ddf8ac23ff69ee4d583888e3f70e Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 21 Jan 2021 21:49:21 +0100
Subject: [PATCH 11/31] Increase coverage

---
 setup.cfg               | 1 +
 telegram/ext/updater.py | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/setup.cfg b/setup.cfg
index 1aebfe10b12..4d5aff02dbf 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -42,6 +42,7 @@ omit =
 [coverage:report]
 exclude_lines =
     if TYPE_CHECKING:
+    ...
 
 [mypy]
 warn_unused_ignores = True
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 7547a6fa08e..f93ab66b44c 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -208,12 +208,12 @@ def __init__(  # type: ignore[no-untyped-def,misc]
                 raise ValueError('`dispatcher` and `bot` are mutually exclusive')
             if persistence is not None:
                 raise ValueError('`dispatcher` and `persistence` are mutually exclusive')
-            if workers is not None:
-                raise ValueError('`dispatcher` and `workers` are mutually exclusive')
             if use_context != dispatcher.use_context:
                 raise ValueError('`dispatcher` and `use_context` are mutually exclusive')
             if context_customizer is not None:
                 raise ValueError('`dispatcher` and `context_customizer` are mutually exclusive')
+            if workers is not None:
+                raise ValueError('`dispatcher` and `workers` are mutually exclusive')
 
         self.logger = logging.getLogger(__name__)
 

From 1ff85031722e33878c3a666f6ad69a5b1a5788f4 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 30 Apr 2021 17:20:55 +0200
Subject: [PATCH 12/31] Start refactoring to introduce
 BasePersistence.refresh_*_data

---
 .../source/telegram.ext.contextcustomizer.rst |   9 -
 docs/source/telegram.ext.contexttypes.rst     |   8 +
 docs/source/telegram.ext.rst                  |   5 +-
 docs/source/telegram.ext.utils.types.rst      |   8 +
 telegram/ext/__init__.py                      |  50 +-
 telegram/ext/basepersistence.py               |  67 +-
 telegram/ext/callbackcontext.py               |  43 +-
 telegram/ext/callbackqueryhandler.py          |   2 +-
 telegram/ext/chatmemberhandler.py             |   2 +-
 telegram/ext/choseninlineresulthandler.py     |   2 +-
 telegram/ext/commandhandler.py                |   3 +-
 telegram/ext/contextcustomizer.py             | 727 ------------------
 telegram/ext/contexttypes.py                  | 202 +++++
 telegram/ext/conversationhandler.py           |   3 +-
 telegram/ext/dictpersistence.py               |  24 +-
 telegram/ext/dispatcher.py                    |  48 +-
 telegram/ext/handler.py                       |  10 +-
 telegram/ext/inlinequeryhandler.py            |   2 +-
 telegram/ext/messagehandler.py                |   2 +-
 telegram/ext/picklepersistence.py             | 142 ++--
 telegram/ext/pollanswerhandler.py             |   2 +-
 telegram/ext/pollhandler.py                   |   2 +-
 telegram/ext/precheckoutqueryhandler.py       |   2 +-
 telegram/ext/regexhandler.py                  |   2 +-
 telegram/ext/shippingqueryhandler.py          |   2 +-
 telegram/ext/stringcommandhandler.py          |   2 +-
 telegram/ext/stringregexhandler.py            |   2 +-
 telegram/ext/typehandler.py                   |   2 +-
 telegram/ext/updater.py                       |  25 +-
 telegram/ext/utils/types.py                   |  32 +
 telegram/utils/types.py                       |  21 -
 tests/test_dispatcher.py                      |   8 +-
 tests/test_jobqueue.py                        |   4 +-
 tests/test_persistence.py                     |   4 +-
 34 files changed, 514 insertions(+), 955 deletions(-)
 delete mode 100644 docs/source/telegram.ext.contextcustomizer.rst
 create mode 100644 docs/source/telegram.ext.contexttypes.rst
 create mode 100644 docs/source/telegram.ext.utils.types.rst
 delete mode 100644 telegram/ext/contextcustomizer.py
 create mode 100644 telegram/ext/contexttypes.py
 create mode 100644 telegram/ext/utils/types.py

diff --git a/docs/source/telegram.ext.contextcustomizer.rst b/docs/source/telegram.ext.contextcustomizer.rst
deleted file mode 100644
index c08954f2d05..00000000000
--- a/docs/source/telegram.ext.contextcustomizer.rst
+++ /dev/null
@@ -1,9 +0,0 @@
-telegram.ext.ContextCustomizer
-==============================
-
-..
-    We manually set the signature here in order to not display all the overload variants
-
-.. autoclass:: telegram.ext.ContextCustomizer(context: Type[CCT], bot_data: Type[BD], chat_data: Type[CD], user_data: Type[UD], chat_data_mapping: Type[UDM], user_data_mapping: Type[CDM])
-    :members:
-    :show-inheritance:
diff --git a/docs/source/telegram.ext.contexttypes.rst b/docs/source/telegram.ext.contexttypes.rst
new file mode 100644
index 00000000000..d0cc0a29a1d
--- /dev/null
+++ b/docs/source/telegram.ext.contexttypes.rst
@@ -0,0 +1,8 @@
+:github_url: https://github.com/python-telegram-bot/python-telegram-bot/blob/master/telegram/ext/contexttypes.py
+
+telegram.ext.ContextTypes
+=========================
+
+.. autoclass:: telegram.ext.ContextTypes
+    :members:
+    :show-inheritance:
diff --git a/docs/source/telegram.ext.rst b/docs/source/telegram.ext.rst
index ea7dede769c..a53c182fd70 100644
--- a/docs/source/telegram.ext.rst
+++ b/docs/source/telegram.ext.rst
@@ -13,7 +13,7 @@ telegram.ext package
     telegram.ext.messagequeue
     telegram.ext.delayqueue
     telegram.ext.callbackcontext
-    telegram.ext.contextcustomizer
+    telegram.ext.contexttypes
     telegram.ext.defaults
 
 Handlers
@@ -54,4 +54,5 @@ utils
 
 .. toctree::
 
-    telegram.ext.utils.promise
\ No newline at end of file
+    telegram.ext.utils.promise
+    telegram.ext.utils.types
\ No newline at end of file
diff --git a/docs/source/telegram.ext.utils.types.rst b/docs/source/telegram.ext.utils.types.rst
new file mode 100644
index 00000000000..5c501ecf840
--- /dev/null
+++ b/docs/source/telegram.ext.utils.types.rst
@@ -0,0 +1,8 @@
+:github_url: https://github.com/python-telegram-bot/python-telegram-bot/blob/master/telegram/ext/utils/types.py
+
+telegram.ext.utils.types Module
+================================
+
+.. automodule:: telegram.ext.utils.types
+    :members:
+    :show-inheritance:
diff --git a/telegram/ext/__init__.py b/telegram/ext/__init__.py
index 9795abf0204..6854f7114c3 100644
--- a/telegram/ext/__init__.py
+++ b/telegram/ext/__init__.py
@@ -23,7 +23,7 @@
 from .dictpersistence import DictPersistence
 from .handler import Handler
 from .callbackcontext import CallbackContext
-from .contextcustomizer import ContextCustomizer
+from .contexttypes import ContextTypes
 from .dispatcher import Dispatcher, DispatcherHandlerStop, run_async
 from .jobqueue import JobQueue, Job
 from .updater import Updater
@@ -48,39 +48,39 @@
 from .defaults import Defaults
 
 __all__ = (
-    'Dispatcher',
-    'JobQueue',
-    'Job',
-    'Updater',
+    'BaseFilter',
+    'BasePersistence',
+    'CallbackContext',
     'CallbackQueryHandler',
+    'ChatMemberHandler',
     'ChosenInlineResultHandler',
     'CommandHandler',
+    'ContextTypes',
+    'ConversationHandler',
+    'Defaults',
+    'DelayQueue',
+    'DictPersistence',
+    'Dispatcher',
+    'DispatcherHandlerStop',
+    'Filters',
     'Handler',
     'InlineQueryHandler',
-    'MessageHandler',
-    'BaseFilter',
+    'Job',
+    'JobQueue',
     'MessageFilter',
-    'UpdateFilter',
-    'Filters',
+    'MessageHandler',
+    'MessageQueue',
+    'PicklePersistence',
+    'PollAnswerHandler',
+    'PollHandler',
+    'PreCheckoutQueryHandler',
+    'PrefixHandler',
     'RegexHandler',
+    'ShippingQueryHandler',
     'StringCommandHandler',
     'StringRegexHandler',
     'TypeHandler',
-    'ConversationHandler',
-    'PreCheckoutQueryHandler',
-    'ShippingQueryHandler',
-    'MessageQueue',
-    'DelayQueue',
-    'DispatcherHandlerStop',
+    'UpdateFilter',
+    'Updater',
     'run_async',
-    'CallbackContext',
-    'BasePersistence',
-    'PicklePersistence',
-    'DictPersistence',
-    'PrefixHandler',
-    'PollAnswerHandler',
-    'PollHandler',
-    'ChatMemberHandler',
-    'Defaults',
-    'ContextCustomizer',
 )
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index d00630e1281..436d5125ae7 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -20,14 +20,15 @@
 import warnings
 from abc import ABC, abstractmethod
 from copy import copy
-from typing import Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping
+from typing import Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping, DefaultDict
 
 from telegram import Bot
 
-from telegram.utils.types import ConversationDict, CD, UD, BD, UDM, CDM
+from telegram.utils.types import ConversationDict
+from telegram.ext.utils.types import UD, CD, BD
 
 
-class BasePersistence(Generic[UD, CD, BD, UDM, CDM], ABC):
+class BasePersistence(Generic[UD, CD, BD], ABC):
     """Interface class for adding persistence to your bot.
     Subclass this object for different implementations of a persistent bot.
 
@@ -35,10 +36,13 @@ class BasePersistence(Generic[UD, CD, BD, UDM, CDM], ABC):
 
     * :meth:`get_bot_data`
     * :meth:`update_bot_data`
+    * :meth:`refresh_bot_data`
     * :meth:`get_chat_data`
     * :meth:`update_chat_data`
+    * :meth:`refresh_chat_data`
     * :meth:`get_user_data`
     * :meth:`update_user_data`
+    * :meth:`refresh_user_data`
     * :meth:`get_conversations`
     * :meth:`update_conversation`
     * :meth:`flush`
@@ -290,33 +294,33 @@ def _insert_bot(self, obj: object, memo: Dict[int, object]) -> object:  # pylint
         return obj
 
     @abstractmethod
-    def get_user_data(self) -> Mapping[int, UD]:
+    def get_user_data(self) -> DefaultDict[int, UD]:
         """Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``user_data`` if stored, or an empty
-        ``Mapping`` with integer keys.
+        :obj:`defaultdict(telegram.ext.utils.types.UD)` with integer keys.
 
         Returns:
-            :obj:`Mapping[int, UD]`: The restored user data.
+            DefaultDict[:obj:`int`, :class:`telegram.ext.utils.types.UD`]: The restored user data.
         """
 
     @abstractmethod
-    def get_chat_data(self) -> Mapping[int, CD]:
+    def get_chat_data(self) -> DefaultDict[int, CD]:
         """Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``chat_data`` if stored, or an empty
-        ``Mapping`` with integer keys.
+        :obj:`defaultdict(telegram.ext.utils.types.CD)` with integer keys.
 
         Returns:
-            :obj:`Mapping[int, Any]`: The restored chat data.
+            DefaultDict[:obj:`int`, :class:`telegram.ext.utils.types.CD`]: The restored chat data.
         """
 
     @abstractmethod
     def get_bot_data(self) -> BD:
         """Will be called by :class:`telegram.ext.Dispatcher` upon creation with a
         persistence object. It should return the ``bot_data`` if stored, or an empty
-        :obj:`dict`.
+        :class:`telegram.ext.utils.types.BD`.
 
         Returns:
-            :obj:`dict`: The restored bot data.
+            :class:`telegram.ext.utils.types.BD`: The restored user data.
         """
 
     @abstractmethod
@@ -353,7 +357,8 @@ def update_user_data(self, user_id: int, data: UD) -> None:
 
         Args:
             user_id (:obj:`int`): The user the data might have been changed for.
-            data (:obj:`UD`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
+            data (:class:`telegram.ext.utils.types.UD`): The
+                :attr:`telegram.ext.dispatcher.user_data` ``[user_id]``.
         """
 
     @abstractmethod
@@ -363,7 +368,8 @@ def update_chat_data(self, chat_id: int, data: CD) -> None:
 
         Args:
             chat_id (:obj:`int`): The chat the data might have been changed for.
-            data (:obj:`CD`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
+            data (:class:`telegram.ext.utils.types.CD`): The
+                :attr:`telegram.ext.dispatcher.chat_data` ``[chat_id]``.
         """
 
     @abstractmethod
@@ -372,9 +378,42 @@ def update_bot_data(self, data: BD) -> None:
         handled an update.
 
         Args:
-            data (:obj:`BD`): The :attr:`telegram.ext.dispatcher.bot_data` .
+            data (:class:`telegram.ext.utils.types.BD`): The
+                :attr:`telegram.ext.dispatcher.bot_data`.
         """
 
+    def refresh_user_data(self, user_id: int, user_data: UD) -> None:
+        """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
+        :attr:`user_data` to a callback. Can be used to update data stored in :attr:`user_data`
+        from an external source.
+
+        Args:
+            user_id (:obj:`int`): The user ID this :attr:`user_data` is associated with.
+            user_data (:class:`telegram.ext.utils.types.UD`): The ``user_data`` of a single user.
+        """
+        raise NotImplementedError
+
+    def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
+        """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
+        :attr:`chat_data` to a callback. Can be used to update data stored in :attr:`chat_data`
+        from an external source.
+
+        Args:
+            chat_id (:obj:`int`): The chat ID this :attr:`chat_data` is associated with.
+            chat_data (:class:`telegram.ext.utils.types.CD`): The ``chat_data`` of a single chat.
+        """
+        raise NotImplementedError
+
+    def refresh_bot_data(self, bot_data: BD) -> None:
+        """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
+        :attr:`bot_data` to a callback. Can be used to update data stored in :attr:`bot_data`
+        from an external source.
+
+        Args:
+            bot_data (:class:`telegram.ext.utils.types.BD`): The ``bot_data``.
+        """
+        raise NotImplementedError
+
     def flush(self) -> None:
         """Will be called by :class:`telegram.ext.Updater` upon receiving a stop signal. Gives the
         persistence a chance to finish up saving or close a database connection gracefully.
diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
index 1b3f90f1087..a0cb08946c5 100644
--- a/telegram/ext/callbackcontext.py
+++ b/telegram/ext/callbackcontext.py
@@ -22,7 +22,7 @@
 from typing import TYPE_CHECKING, Dict, List, Match, NoReturn, Optional, Tuple, Union, Generic
 
 from telegram import Update
-from telegram.utils.types import UD, CD, BD
+from telegram.ext.utils.types import UD, CD, BD
 
 if TYPE_CHECKING:
     from telegram import Bot
@@ -87,9 +87,8 @@ def __init__(self, dispatcher: 'Dispatcher'):
                 'CallbackContext should not be used with a non context aware ' 'dispatcher!'
             )
         self._dispatcher = dispatcher
-        self._bot_data = dispatcher.bot_data
-        self._chat_data: Optional[CD] = None
-        self._user_data: Optional[UD] = None
+        self._chat_id_and_data: Optional[Tuple[int, CD]] = None
+        self._user_id_and_data: Optional[Tuple[int, UD]] = None
         self.args: Optional[List[str]] = None
         self.matches: Optional[List[Match]] = None
         self.error: Optional[Exception] = None
@@ -108,7 +107,7 @@ def bot_data(self) -> BD:
         bot_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
             update it will be the same :obj:`dict`.
         """
-        return self._bot_data
+        return self.dispatcher.bot_data
 
     @bot_data.setter
     def bot_data(self, value: object) -> NoReturn:
@@ -129,7 +128,9 @@ def chat_data(self) -> Optional[CD]:
                 <https://github.com/python-telegram-bot/python-telegram-bot/wiki/
                 Storing-user--and-chat-related-data#chat-migration>`_.
         """
-        return self._chat_data
+        if self._chat_id_and_data:
+            return self._chat_id_and_data[1]
+        return None
 
     @chat_data.setter
     def chat_data(self, value: object) -> NoReturn:
@@ -143,7 +144,9 @@ def user_data(self) -> Optional[UD]:
         user_data (:obj:`dict`): Optional. A dict that can be used to keep any data in. For each
             update from the same user it will be the same :obj:`dict`.
         """
-        return self._user_data
+        if self._user_id_and_data:
+            return self._user_id_and_data[1]
+        return None
 
     @user_data.setter
     def user_data(self, value: object) -> NoReturn:
@@ -151,6 +154,22 @@ def user_data(self, value: object) -> NoReturn:
             "You can not assign a new value to user_data, see https://git.io/Jt6ic"
         )
 
+    def refresh_data(self) -> None:
+        """
+        If :attr:`dispatcher` uses persistence, calls
+        :meth:`telegram.ext.BasePersistence.refresh_bot_data` on :attr:`bot_data`,
+        :meth:`telegram.ext.BasePersistence.refresh_chat_data` on :attr:`chat_data`,
+        :meth:`telegram.ext.BasePersistence.refresh_user_data` on :attr:`user_data`, if
+        appropriate.
+        """
+        if self.dispatcher.persistence:
+            if self.dispatcher.persistence.store_bot_data:
+                self.dispatcher.persistence.refresh_bot_data(self.bot_data)
+            if self.dispatcher.persistence.store_chat_data and self._chat_id_and_data is not None:
+                self.dispatcher.persistence.refresh_chat_data(*self._chat_id_and_data)
+            if self.dispatcher.persistence.store_user_data and self._user_id_and_data is not None:
+                self.dispatcher.persistence.refresh_user_data(*self._user_id_and_data)
+
     @classmethod
     def from_error(
         cls,
@@ -213,9 +232,15 @@ def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CallbackConte
             user = update.effective_user
 
             if chat:
-                self._chat_data = dispatcher.chat_data[chat.id]  # pylint: disable=W0212
+                self._chat_id_and_data = (
+                    chat.id,
+                    dispatcher.chat_data[chat.id],  # pylint: disable=W0212
+                )
             if user:
-                self._user_data = dispatcher.user_data[user.id]  # pylint: disable=W0212
+                self._user_id_and_data = (
+                    user.id,
+                    dispatcher.user_data[user.id],  # pylint: disable=W0212
+                )
         return self
 
     @classmethod
diff --git a/telegram/ext/callbackqueryhandler.py b/telegram/ext/callbackqueryhandler.py
index a43d6f6d5c3..9b814a0bdc6 100644
--- a/telegram/ext/callbackqueryhandler.py
+++ b/telegram/ext/callbackqueryhandler.py
@@ -35,7 +35,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/chatmemberhandler.py b/telegram/ext/chatmemberhandler.py
index bcacc2f3c81..49cef232811 100644
--- a/telegram/ext/chatmemberhandler.py
+++ b/telegram/ext/chatmemberhandler.py
@@ -22,7 +22,7 @@
 from telegram import Update
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 RT = TypeVar('RT')
 
diff --git a/telegram/ext/choseninlineresulthandler.py b/telegram/ext/choseninlineresulthandler.py
index 4b72214120e..9217b7df3b7 100644
--- a/telegram/ext/choseninlineresulthandler.py
+++ b/telegram/ext/choseninlineresulthandler.py
@@ -23,7 +23,7 @@
 from telegram import Update
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 RT = TypeVar('RT')
 
diff --git a/telegram/ext/commandhandler.py b/telegram/ext/commandhandler.py
index abee45e5e58..f2acd195e24 100644
--- a/telegram/ext/commandhandler.py
+++ b/telegram/ext/commandhandler.py
@@ -24,9 +24,10 @@
 from telegram import MessageEntity, Update
 from telegram.ext import BaseFilter, Filters
 from telegram.utils.deprecate import TelegramDeprecationWarning
-from telegram.utils.types import SLT, CCT
+from telegram.utils.types import SLT
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
+from .utils.types import CCT
 from .handler import Handler
 
 if TYPE_CHECKING:
diff --git a/telegram/ext/contextcustomizer.py b/telegram/ext/contextcustomizer.py
deleted file mode 100644
index 880a75e2f89..00000000000
--- a/telegram/ext/contextcustomizer.py
+++ /dev/null
@@ -1,727 +0,0 @@
-#!/usr/bin/env python
-#
-# A library that provides a Python interface to the Telegram Bot API
-# Copyright (C) 2020
-# Leandro Toledo de Souza <devs@python-telegram-bot.org>
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Lesser Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Lesser Public License for more details.
-#
-# You should have received a copy of the GNU Lesser Public License
-# along with this program.  If not, see [http://www.gnu.org/licenses/].
-# pylint: disable=R0201
-"""This module contains the auxiliary class ContextCustomizer."""
-from collections import defaultdict
-from collections.abc import Mapping
-from typing import Type, Any, NoReturn, Generic, overload, Dict  # pylint: disable=W0611
-
-from telegram.ext.callbackcontext import CallbackContext
-from telegram.utils.types import CCT, UD, CD, BD, CDM, UDM, IntDD  # pylint: disable=W0611
-
-
-class ContextCustomizer(Generic[CCT, UD, CD, BD, UDM, CDM]):
-    """
-    Convenience class to gather customizable types of the ``context`` interface.
-
-    Args:
-        context (:obj:`type`, optional): Determines the type of the ``context`` argument of all
-            (error-)handler callbacks and job callbacks. Must be a subclass of
-            :class:`telegram.ext.CallbackContext`. Defaults to
-            :class:`telegram.ext.CallbackContext`.
-        bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data`` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
-            instantiating without arguments.
-        chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data`` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
-        user_data (:obj:`type`, optional): Determines the type of ``context.user_data`` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
-        chat_data_mapping (:obj:`type`, optional): In combination with :attr:`chat_data` determines
-            the type of :attr:`telegram.ext.Dispatcher.chat_data`. Must be a subclass of
-            :obj:`collections.abc.Mapping` with integer keys supporting instantiating via
-
-            .. code:: python
-
-                chat_data_mapping(chat_data)
-
-            Defaults to :obj:`defaultdict`.
-
-        user_data_mapping (:obj:`type`, optional): In combination with :attr:`user_data` determines
-            the type of :attr:`telegram.ext.Dispatcher.user_data`. Must be a subclass of
-            :obj:`collections.abc.Mapping` with integer keys supporting instantiating via
-
-            .. code:: python
-
-                user_data_mapping(user_data)
-
-            Defaults to :obj:`defaultdict`.
-
-    """
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, "
-        "IntDD[Dict], IntDD[Dict]]",
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, Dict, IntDD[Dict], IntDD[Dict]]",
-        context: Type[CCT],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
-        "IntDD[UD], IntDD[Dict]]",
-        bot_data: Type[BD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
-        "IntDD[Dict], IntDD[CD]]",
-        chat_data: Type[CD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, "
-        "IntDD[Dict], IntDD[Dict]]",
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, "
-        "Dict, UDM, IntDD[Dict]]",
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, "
-        "IntDD[Dict], CDM]",
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, Dict, IntDD[UD], IntDD[Dict]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, Dict, IntDD[Dict], IntDD[CD]]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, BD, IntDD[Dict], IntDD[Dict]]",
-        context: Type[CCT],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, Dict, UDM, IntDD[Dict]]",
-        context: Type[CCT],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, Dict, IntDD[Dict], CDM]",
-        context: Type[CCT],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, "
-        "IntDD[UD], IntDD[CD]]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, "
-        "IntDD[UD], IntDD[Dict]]",
-        bot_data: Type[BD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
-        "UDM, IntDD[Dict]]",
-        bot_data: Type[BD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, "
-        "IntDD[UD], CDM]",
-        bot_data: Type[BD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, "
-        "IntDD[Dict], IntDD[CD]]",
-        chat_data: Type[CD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
-        "UDM, IntDD[CD]]",
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, "
-        "IntDD[Dict], CDM]",
-        chat_data: Type[CD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, UDM, "
-        "IntDD[Dict]]",
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, "
-        "IntDD[Dict], CDM]",
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, UDM, CDM]",
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, Dict, IntDD[UD], IntDD[CD]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, BD, IntDD[UD], IntDD[Dict]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, Dict, UDM, IntDD[Dict]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, Dict, IntDD[UD], CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, BD, IntDD[Dict], IntDD[CD]]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, Dict, UDM, IntDD[CD]]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, Dict, IntDD[Dict], CDM]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, BD, UDM, IntDD[Dict]]",
-        context: Type[CCT],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, BD, IntDD[Dict], CDM]",
-        context: Type[CCT],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, Dict, UDM, CDM]",
-        context: Type[CCT],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, IntDD[UD], IntDD[CD]]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, UDM, IntDD[CD]]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, IntDD[UD], CDM]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, UDM, IntDD[Dict]]",
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, IntDD[UD], CDM]",
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, Dict], UD, Dict, Dict, UDM, CDM]",
-        bot_data: Type[BD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, UDM, IntDD[CD]]",
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, IntDD[Dict], CDM]",
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, Dict], Dict, CD, Dict, UDM, CDM]",
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, Dict, BD], Dict, Dict, BD, UDM, CDM]",
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, IntDD[UD], IntDD[CD]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, Dict, UDM, IntDD[CD]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, Dict, IntDD[UD], CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, BD, UDM, IntDD[Dict]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, BD, IntDD[UD], CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, Dict, UDM, CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, BD, UDM, IntDD[CD]]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, BD, IntDD[Dict], CDM]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, Dict, UDM, CDM]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, Dict, BD, UDM, CDM]",
-        context: Type[CCT],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, UDM, IntDD[CD]]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, IntDD[UD], CDM]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, Dict], UD, CD, Dict, UDM, CDM]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, Dict, BD], UD, Dict, BD, UDM, CDM]",
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[Dict, CD, BD], Dict, CD, BD, UDM, CDM]",
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, IntDD[CD]]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, IntDD[UD], CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, Dict, UDM, CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, Dict, BD, UDM, CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, Dict, CD, BD, UDM, CDM]",
-        context: Type[CCT],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CallbackContext[UD, CD, BD], UD, CD, BD, UDM, CDM]",
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    @overload
-    def __init__(
-        self: "ContextCustomizer[CCT, UD, CD, BD, UDM, CDM]",
-        context: Type[CCT],
-        bot_data: Type[BD],
-        chat_data: Type[CD],
-        user_data: Type[UD],
-        chat_data_mapping: Type[UDM],
-        user_data_mapping: Type[CDM],
-    ):
-        ...
-
-    def __init__(  # type: ignore[no-untyped-def]
-        self,
-        context=CallbackContext,
-        bot_data=dict,
-        chat_data=dict,
-        user_data=dict,
-        chat_data_mapping=defaultdict,
-        user_data_mapping=defaultdict,
-    ):
-        if not issubclass(context, CallbackContext):
-            raise ValueError('context must be a subclass of CallbackContext.')
-        if not issubclass(chat_data_mapping, Mapping):
-            raise ValueError('chat_data_mapping must be a subclass of collections.Mapping.')
-        if not issubclass(user_data_mapping, Mapping):
-            raise ValueError('user_data_mapping must be a subclass of collections.Mapping.')
-
-        self._context = context
-        self._bot_data = bot_data
-        self._chat_data = chat_data
-        self._user_data = user_data
-        self._chat_data_mapping = chat_data_mapping
-        self._user_data_mapping = user_data_mapping
-
-    @property
-    def context(self) -> Type[CCT]:
-        return self._context
-
-    @context.setter
-    def context(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
-
-    @property
-    def bot_data(self) -> Type[BD]:
-        return self._bot_data
-
-    @bot_data.setter
-    def bot_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
-
-    @property
-    def chat_data(self) -> Type[CD]:
-        return self._chat_data
-
-    @chat_data.setter
-    def chat_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
-
-    @property
-    def user_data(self) -> Type[UD]:
-        return self._user_data
-
-    @user_data.setter
-    def user_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
-
-    @property
-    def user_data_mapping(self) -> Type[UDM]:
-        return self._user_data_mapping
-
-    @user_data_mapping.setter
-    def user_data_mapping(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
-
-    @property
-    def chat_data_mapping(self) -> Type[CDM]:
-        return self._chat_data_mapping
-
-    @chat_data_mapping.setter
-    def chat_data_mapping(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextCustomizer attributes.")
diff --git a/telegram/ext/contexttypes.py b/telegram/ext/contexttypes.py
new file mode 100644
index 00000000000..10286e40c2e
--- /dev/null
+++ b/telegram/ext/contexttypes.py
@@ -0,0 +1,202 @@
+#!/usr/bin/env python
+#
+# A library that provides a Python interface to the Telegram Bot API
+# Copyright (C) 2020
+# Leandro Toledo de Souza <devs@python-telegram-bot.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser Public License for more details.
+#
+# You should have received a copy of the GNU Lesser Public License
+# along with this program.  If not, see [http://www.gnu.org/licenses/].
+# pylint: disable=R0201
+"""This module contains the auxiliary class ContextTypes."""
+from typing import Type, Any, NoReturn, Generic, overload, Dict  # pylint: disable=W0611
+
+from telegram.ext.callbackcontext import CallbackContext
+from telegram.ext.utils.types import CCT, UD, CD, BD
+
+
+class ContextTypes(Generic[CCT, UD, CD, BD]):
+    """
+    Convenience class to gather customizable types of the :class:`telegram.ext.CallbackContext`
+    interface.
+
+    Args:
+        context (:obj:`type`, optional): Determines the type of the ``context`` argument of all
+            (error-)handler callbacks and job callbacks. Must be a subclass of
+            :class:`telegram.ext.CallbackContext`. Defaults to
+            :class:`telegram.ext.CallbackContext`.
+        bot_data (:obj:`type`, optional): Determines the type of ``context.bot_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            instantiating without arguments.
+        chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+        user_data (:obj:`type`, optional): Determines the type of ``context.user_data`` of all
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+
+    """
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CallbackContext, Dict, Dict, Dict]',
+    ):
+        ...
+
+    @overload
+    def __init__(self: 'ContextTypes[CCT, Dict, Dict, Dict]', context: Type[CCT]):
+        ...
+
+    @overload
+    def __init__(self: 'ContextTypes[CallbackContext, UD, Dict, Dict]', bot_data: Type[UD]):
+        ...
+
+    @overload
+    def __init__(self: 'ContextTypes[CallbackContext, Dict, CD, Dict]', chat_data: Type[CD]):
+        ...
+
+    @overload
+    def __init__(self: 'ContextTypes[CallbackContext, Dict, Dict, BD]', user_data: Type[BD]):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, UD, Dict, Dict]', context: Type[CCT], bot_data: Type[UD]
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, Dict, CD, Dict]', context: Type[CCT], chat_data: Type[CD]
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, Dict, Dict, BD]', context: Type[CCT], user_data: Type[BD]
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CallbackContext, UD, CD, Dict]',
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CallbackContext, UD, Dict, BD]',
+        bot_data: Type[UD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CallbackContext, Dict, CD, BD]',
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, UD, CD, Dict]',
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, UD, Dict, BD]',
+        context: Type[CCT],
+        bot_data: Type[UD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, Dict, CD, BD]',
+        context: Type[CCT],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CallbackContext, UD, CD, BD]',
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    @overload
+    def __init__(
+        self: 'ContextTypes[CCT, UD, CD, BD]',
+        context: Type[CCT],
+        bot_data: Type[UD],
+        chat_data: Type[CD],
+        user_data: Type[BD],
+    ):
+        ...
+
+    def __init__(  # type: ignore[no-untyped-def]
+        self,
+        context=CallbackContext,
+        bot_data=dict,
+        chat_data=dict,
+        user_data=dict,
+    ):
+        if not issubclass(context, CallbackContext):
+            raise ValueError('context must be a subclass of CallbackContext.')
+
+        self._context = context
+        self._bot_data = bot_data
+        self._chat_data = chat_data
+        self._user_data = user_data
+
+    @property
+    def context(self) -> Type[CCT]:
+        return self._context
+
+    @context.setter
+    def context(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
+
+    @property
+    def bot_data(self) -> Type[BD]:
+        return self._bot_data
+
+    @bot_data.setter
+    def bot_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
+
+    @property
+    def chat_data(self) -> Type[CD]:
+        return self._chat_data
+
+    @chat_data.setter
+    def chat_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
+
+    @property
+    def user_data(self) -> Type[UD]:
+        return self._user_data
+
+    @user_data.setter
+    def user_data(self, value: Any) -> NoReturn:
+        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
diff --git a/telegram/ext/conversationhandler.py b/telegram/ext/conversationhandler.py
index 157e79f6d6b..e36c32aab18 100644
--- a/telegram/ext/conversationhandler.py
+++ b/telegram/ext/conversationhandler.py
@@ -37,7 +37,8 @@
     InlineQueryHandler,
 )
 from telegram.ext.utils.promise import Promise
-from telegram.utils.types import ConversationDict, CCT
+from telegram.utils.types import ConversationDict
+from telegram.ext.utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher, Job
diff --git a/telegram/ext/dictpersistence.py b/telegram/ext/dictpersistence.py
index 572a27e85a7..7224356a881 100644
--- a/telegram/ext/dictpersistence.py
+++ b/telegram/ext/dictpersistence.py
@@ -37,7 +37,7 @@
 
 
 class DictPersistence(BasePersistence):
-    """Using python's dicts and json for making your bot persistent.
+    """Using Python's :obj:`dict` and ``json`` for making your bot persistent.
 
     Note:
         This class does *not* implement a :meth:`flush` method, meaning that data managed by
@@ -253,7 +253,7 @@ def update_user_data(self, user_id: int, data: Dict) -> None:
 
         Args:
             user_id (:obj:`int`): The user the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
+            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` ``[user_id]``.
         """
         if self._user_data is None:
             self._user_data = defaultdict(dict)
@@ -267,7 +267,7 @@ def update_chat_data(self, chat_id: int, data: Dict) -> None:
 
         Args:
             chat_id (:obj:`int`): The chat the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
+            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` ``[chat_id]``.
         """
         if self._chat_data is None:
             self._chat_data = defaultdict(dict)
@@ -286,3 +286,21 @@ def update_bot_data(self, data: Dict) -> None:
             return
         self._bot_data = data.copy()
         self._bot_data_json = None
+
+    def refresh_user_data(self, user_id: int, user_data: Dict) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_user_data`
+        """
+
+    def refresh_chat_data(self, chat_id: int, chat_data: Dict) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_chat_data`
+        """
+
+    def refresh_bot_data(self, bot_data: Dict) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_bot_data`
+        """
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index 1a1ac90912c..faf060908fd 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -21,6 +21,7 @@
 import logging
 import warnings
 import weakref
+from collections import defaultdict
 from functools import wraps
 from queue import Empty, Queue
 from threading import BoundedSemaphore, Event, Lock, Thread, current_thread
@@ -37,17 +38,18 @@
     TypeVar,
     overload,
     cast,
+    DefaultDict,
 )
 from uuid import uuid4
 
 from telegram import TelegramError, Update
-from telegram.ext import BasePersistence, ContextCustomizer
+from telegram.ext import BasePersistence, ContextTypes
 from telegram.ext.callbackcontext import CallbackContext
 from telegram.ext.handler import Handler
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.ext.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
-from telegram.utils.types import CCT, UD, CD, BD, UDM, CDM, IntDD  # pylint: disable=W0611
+from telegram.ext.utils.types import CCT, UD, CD, BD
 
 if TYPE_CHECKING:
     from telegram import Bot
@@ -117,7 +119,7 @@ def __init__(self, state: object = None) -> None:
         self.state = state
 
 
-class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
+class Dispatcher(Generic[CCT, UD, CD, BD]):
     """This class dispatches all kinds of updates to its registered handlers.
 
     Args:
@@ -149,7 +151,7 @@ class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
         bot_data (:obj:`dict`): A dictionary handlers can use to store data for the bot.
         persistence (:class:`telegram.ext.BasePersistence`): Optional. The persistence class to
             store data that should be persistent over restarts.
-        context_customizer (:class:`telegram.ext.ContextCustomizer`): Container for the types used
+        context_customizer (:class:`telegram.ext.ContextTypes`): Container for the types used
             in the ``context`` interface.
 
     """
@@ -161,8 +163,7 @@ class Dispatcher(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     @overload
     def __init__(
-        self: 'Dispatcher[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict, '
-        'IntDD[Dict], IntDD[Dict]]',
+        self: 'Dispatcher[CallbackContext[Dict, Dict, Dict], Dict, Dict, Dict]',
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
@@ -175,7 +176,7 @@ def __init__(
 
     @overload
     def __init__(
-        self: 'Dispatcher[CCT, UD, CD, BD, UDM, CDM]',
+        self: 'Dispatcher[CCT, UD, CD, BD]',
         bot: 'Bot',
         update_queue: Queue,
         workers: int = 4,
@@ -183,7 +184,7 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         ...
 
@@ -196,7 +197,7 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         self.bot = bot
         self.update_queue = update_queue
@@ -204,7 +205,7 @@ def __init__(
         self.workers = workers
         self.use_context = use_context
         self.context_customizer = cast(
-            ContextCustomizer[CCT, UD, CD, BD, UDM, CDM], context_customizer or ContextCustomizer()
+            ContextTypes[CCT, UD, CD, BD], context_customizer or ContextTypes()
         )
 
         if not use_context:
@@ -219,12 +220,8 @@ def __init__(
                 'Asynchronous callbacks can not be processed without at least one worker thread.'
             )
 
-        self.user_data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-            self.context_customizer.user_data
-        )
-        self.chat_data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-            self.context_customizer.chat_data
-        )
+        self.user_data: DefaultDict[int, UD] = defaultdict(self.context_customizer.user_data)
+        self.chat_data: DefaultDict[int, CD] = defaultdict(self.context_customizer.chat_data)
         self.bot_data = self.context_customizer.bot_data()
         self.persistence: Optional[BasePersistence] = None
         self._update_persistence_lock = Lock()
@@ -234,19 +231,13 @@ def __init__(
             self.persistence = persistence
             self.persistence.set_bot(self.bot)
             if self.persistence.store_user_data:
-                self.user_data = self.persistence.get_user_data()  # type: ignore[assignment]
-                if not isinstance(self.user_data, self.context_customizer.user_data_mapping):
-                    raise ValueError(
-                        f"user_data must be of type "
-                        f"{self.context_customizer.user_data_mapping.__name__}"
-                    )
+                self.user_data = self.persistence.get_user_data()
+                if not isinstance(self.user_data, defaultdict):
+                    raise ValueError("user_data must be of type defaultdict")
             if self.persistence.store_chat_data:
-                self.chat_data = self.persistence.get_chat_data()  # type: ignore[assignment]
-                if not isinstance(self.chat_data, self.context_customizer.chat_data_mapping):
-                    raise ValueError(
-                        f"chat_data must be of type "
-                        f"{self.context_customizer.chat_data_mapping.__name__}"
-                    )
+                self.chat_data = self.persistence.get_chat_data()
+                if not isinstance(self.chat_data, defaultdict):
+                    raise ValueError("chat_data must be of type defaultdict")
             if self.persistence.store_bot_data:
                 self.bot_data = self.persistence.get_bot_data()
                 if not isinstance(self.bot_data, self.context_customizer.bot_data):
@@ -507,6 +498,7 @@ def process_update(self, update: object) -> None:
                     if check is not None and check is not False:
                         if not context and self.use_context:
                             context = self.context_customizer.context.from_update(update, self)
+                            context.refresh_data()
                         handled = True
                         sync_modes.append(handler.run_async)
                         handler.handle_update(update, self, check, context)
diff --git a/telegram/ext/handler.py b/telegram/ext/handler.py
index e8f39441502..6b36e081d98 100644
--- a/telegram/ext/handler.py
+++ b/telegram/ext/handler.py
@@ -24,7 +24,7 @@
 from telegram import Update
 from telegram.ext.utils.promise import Promise
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
-from telegram.utils.types import CCT
+from telegram.ext.utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
@@ -211,9 +211,13 @@ def collect_optional_args(
             optional_args['job_queue'] = dispatcher.job_queue
         if self.pass_user_data and isinstance(update, Update):
             user = update.effective_user
-            optional_args['user_data'] = dispatcher.user_data[user.id if user else None]
+            optional_args['user_data'] = dispatcher.user_data[
+                user.id if user else None  # type: ignore[index]
+            ]
         if self.pass_chat_data and isinstance(update, Update):
             chat = update.effective_chat
-            optional_args['chat_data'] = dispatcher.chat_data[chat.id if chat else None]
+            optional_args['chat_data'] = dispatcher.chat_data[
+                chat.id if chat else None  # type: ignore[index]
+            ]
 
         return optional_args
diff --git a/telegram/ext/inlinequeryhandler.py b/telegram/ext/inlinequeryhandler.py
index 6124430aaa9..b9d9fc5cdf2 100644
--- a/telegram/ext/inlinequeryhandler.py
+++ b/telegram/ext/inlinequeryhandler.py
@@ -35,7 +35,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/messagehandler.py b/telegram/ext/messagehandler.py
index 0524dcb07c2..39be657d01b 100644
--- a/telegram/ext/messagehandler.py
+++ b/telegram/ext/messagehandler.py
@@ -27,7 +27,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index ac55654f97c..3586c386210 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -18,17 +18,24 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains the PicklePersistence class."""
 import pickle
-from typing import Any, Dict, Optional, Tuple, overload, Mapping, cast, TypeVar, MutableMapping
+from collections import defaultdict
+from typing import (
+    Any,
+    Dict,
+    Optional,
+    Tuple,
+    overload,
+    cast,
+    DefaultDict,
+)
 
 from telegram.ext import BasePersistence
-from telegram.utils.types import ConversationDict, CD, UD, BD, IntDD  # pylint: disable=W0611
-from .contextcustomizer import ContextCustomizer
+from telegram.utils.types import ConversationDict  # pylint: disable=W0611
+from .utils.types import UD, CD, BD
+from .contexttypes import ContextTypes
 
-UDM = TypeVar('UDM', bound=MutableMapping)
-CDM = TypeVar('CDM', bound=MutableMapping)
 
-
-class PicklePersistence(BasePersistence[UD, CD, BD, UDM, CDM]):
+class PicklePersistence(BasePersistence[UD, CD, BD]):
     """Using python's builtin pickle for making you bot persistent.
 
     Warning:
@@ -58,20 +65,7 @@ class PicklePersistence(BasePersistence[UD, CD, BD, UDM, CDM]):
             Default is :obj:`False`.
         context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
             of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
-            ``context`` interface.
-
-            Note:
-                The types for :attr:`telegram.ext.ContextCustomizer.user_data_mapping` and
-                :attr:`telegram.ext.ContextCustomizer.chat_data_mapping` must be subclasses of
-                :class:`collections.abc.MutableMapping` and support instantiation via
-
-                .. code:: python
-
-                    chat/user_data_mapping(chat/user_data_type[, data])
-
-                where ``data`` is of type ``chat/user_data_mapping``.
-
-            If not passed, the defaults documented in
+            ``context`` interface. If not passed, the defaults documented in
             :class:`telegram.ext.ContextCustomizer` will be used.
 
     Attributes:
@@ -90,13 +84,13 @@ class PicklePersistence(BasePersistence[UD, CD, BD, UDM, CDM]):
             :meth:`flush` is called and keep data in memory until that happens. When
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
-        context_customizer (:class:`telegram.ext.ContextCustomizer`): Container for the types used
+        context_customizer (:class:`telegram.ext.ContextTypes`): Container for the types used
             in the ``context`` interface.
     """
 
     @overload
     def __init__(
-        self: 'PicklePersistence[Dict, Dict, Dict, IntDD[Dict], IntDD[Dict]]',
+        self: 'PicklePersistence[Dict, Dict, Dict]',
         filename: str,
         store_user_data: bool = True,
         store_chat_data: bool = True,
@@ -108,14 +102,14 @@ def __init__(
 
     @overload
     def __init__(
-        self: 'PicklePersistence[UD, CD, BD, UDM, CDM]',
+        self: 'PicklePersistence[UD, CD, BD]',
         filename: str,
         store_user_data: bool = True,
         store_chat_data: bool = True,
         store_bot_data: bool = True,
         single_file: bool = True,
         on_flush: bool = False,
-        context_customizer: ContextCustomizer[Any, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[Any, UD, CD, BD] = None,
     ):
         ...
 
@@ -127,7 +121,7 @@ def __init__(
         store_bot_data: bool = True,
         single_file: bool = True,
         on_flush: bool = False,
-        context_customizer: ContextCustomizer[Any, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[Any, UD, CD, BD] = None,
     ):
         super().__init__(
             store_user_data=store_user_data,
@@ -137,12 +131,12 @@ def __init__(
         self.filename = filename
         self.single_file = single_file
         self.on_flush = on_flush
-        self.user_data: Optional[MutableMapping[int, UD]] = None
-        self.chat_data: Optional[MutableMapping[int, CD]] = None
+        self.user_data: Optional[DefaultDict[int, UD]] = None
+        self.chat_data: Optional[DefaultDict[int, CD]] = None
         self.bot_data: Optional[BD] = None
         self.conversations: Optional[Dict[str, Dict[Tuple, object]]] = None
         self.context_customizer = cast(
-            ContextCustomizer[Any, UD, CD, BD, UDM, CDM], context_customizer or ContextCustomizer()
+            ContextTypes[Any, UD, CD, BD], context_customizer or ContextTypes()
         )
 
     def load_singlefile(self) -> None:
@@ -150,27 +144,15 @@ def load_singlefile(self) -> None:
             filename = self.filename
             with open(self.filename, "rb") as file:
                 data = pickle.load(file)
-                self.user_data = (
-                    self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-                        self.context_customizer.user_data, data['user_data']
-                    )
-                )
-                self.chat_data = (
-                    self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-                        self.context_customizer.chat_data, data['chat_data']
-                    )
-                )
+                self.user_data = defaultdict(self.context_customizer.user_data, data['user_data'])
+                self.chat_data = defaultdict(self.context_customizer.chat_data, data['chat_data'])
                 # For backwards compatibility with files not containing bot data
                 self.bot_data = data.get('bot_data', self.context_customizer.bot_data())
                 self.conversations = data['conversations']
         except OSError:
             self.conversations = {}
-            self.user_data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-                self.context_customizer.user_data
-            )
-            self.chat_data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-                self.context_customizer.chat_data
-            )
+            self.user_data = defaultdict(self.context_customizer.user_data)
+            self.chat_data = defaultdict(self.context_customizer.chat_data)
             self.bot_data = self.context_customizer.bot_data()
         except pickle.UnpicklingError as exc:
             raise TypeError(f"File {filename} does not contain valid pickle data") from exc
@@ -204,11 +186,11 @@ def dump_file(filename: str, data: object) -> None:
         with open(filename, "wb") as file:
             pickle.dump(data, file)
 
-    def get_user_data(self) -> Mapping[int, UD]:
+    def get_user_data(self) -> DefaultDict[int, UD]:
         """Returns the user_data from the pickle file if it exists or an empty :obj:`defaultdict`.
 
         Returns:
-            :obj:`defaultdict`: The restored user data.
+            DefaultDict[:obj:`int`, :class:`telegram.ext.utils.types.UD`]: The restored user data.
         """
         if self.user_data:
             pass
@@ -216,23 +198,19 @@ def get_user_data(self) -> Mapping[int, UD]:
             filename = f"{self.filename}_user_data"
             data = self.load_file(filename)
             if not data:
-                data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.user_data
-                )
+                data = defaultdict(self.context_customizer.user_data)
             else:
-                data = self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.user_data, data
-                )
+                data = defaultdict(self.context_customizer.user_data, data)
             self.user_data = data
         else:
             self.load_singlefile()
         return self.user_data  # type: ignore[return-value]
 
-    def get_chat_data(self) -> Mapping[int, CD]:
+    def get_chat_data(self) -> DefaultDict[int, CD]:
         """Returns the chat_data from the pickle file if it exists or an empty :obj:`defaultdict`.
 
         Returns:
-            :obj:`defaultdict`: The restored chat data.
+            DefaultDict[:obj:`int`, :class:`telegram.ext.utils.types.CD`]: The restored chat data.
         """
         if self.chat_data:
             pass
@@ -240,23 +218,20 @@ def get_chat_data(self) -> Mapping[int, CD]:
             filename = f"{self.filename}_chat_data"
             data = self.load_file(filename)
             if not data:
-                data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.chat_data
-                )
+                data = defaultdict(self.context_customizer.chat_data)
             else:
-                data = self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.chat_data, data
-                )
+                data = defaultdict(self.context_customizer.chat_data, data)
             self.chat_data = data
         else:
             self.load_singlefile()
         return self.chat_data  # type: ignore[return-value]
 
     def get_bot_data(self) -> BD:
-        """Returns the bot_data from the pickle file if it exists or an empty :obj:`dict`.
+        """Returns the bot_data from the pickle file if it exists or an empty object of type
+        :class:`telegram.ext.utils.types.BD`.
 
         Returns:
-            :obj:`dict`: The restored bot data.
+            :class:`telegram.ext.utils.types.BD`: The restored user data.
         """
         if self.bot_data:
             pass
@@ -319,15 +294,11 @@ def update_user_data(self, user_id: int, data: UD) -> None:
 
         Args:
             user_id (:obj:`int`): The user the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.user_data` [user_id].
+            data (:class:`telegram.ext.utils.types.UD`): The
+                :attr:`telegram.ext.dispatcher.user_data` ``[user_id]``.
         """
         if self.user_data is None:
-            self.user_data = cast(
-                MutableMapping[int, UD],
-                self.context_customizer.user_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.user_data
-                ),
-            )
+            self.user_data = defaultdict(self.context_customizer.user_data)
         if self.user_data.get(user_id) == data:
             return
         self.user_data[user_id] = data
@@ -343,15 +314,11 @@ def update_chat_data(self, chat_id: int, data: CD) -> None:
 
         Args:
             chat_id (:obj:`int`): The chat the data might have been changed for.
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.chat_data` [chat_id].
+            data (:class:`telegram.ext.utils.types.CD`): The
+                :attr:`telegram.ext.dispatcher.chat_data` ``[chat_id]``.
         """
         if self.chat_data is None:
-            self.chat_data = cast(
-                MutableMapping[int, CD],
-                self.context_customizer.chat_data_mapping(  # type: ignore[call-arg]
-                    self.context_customizer.chat_data
-                ),
-            )
+            self.chat_data = defaultdict(self.context_customizer.chat_data)
         if self.chat_data.get(chat_id) == data:
             return
         self.chat_data[chat_id] = data
@@ -366,7 +333,8 @@ def update_bot_data(self, data: BD) -> None:
         """Will update the bot_data and depending on :attr:`on_flush` save the pickle file.
 
         Args:
-            data (:obj:`dict`): The :attr:`telegram.ext.dispatcher.bot_data`.
+            data (:class:`telegram.ext.utils.types.BD`): The
+                :attr:`telegram.ext.dispatcher.bot_data`.
         """
         if self.bot_data == data:
             return
@@ -378,6 +346,24 @@ def update_bot_data(self, data: BD) -> None:
             else:
                 self.dump_singlefile()
 
+    def refresh_user_data(self, user_id: int, user_data: UD) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_user_data`
+        """
+
+    def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_chat_data`
+        """
+
+    def refresh_bot_data(self, bot_data: BD) -> None:
+        """Does nothing.
+
+        .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_bot_data`
+        """
+
     def flush(self) -> None:
         """Will save all data in memory to pickle file(s)."""
         if self.single_file:
diff --git a/telegram/ext/pollanswerhandler.py b/telegram/ext/pollanswerhandler.py
index e8a23ca6286..80c174f13a6 100644
--- a/telegram/ext/pollanswerhandler.py
+++ b/telegram/ext/pollanswerhandler.py
@@ -22,7 +22,7 @@
 from telegram import Update
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 
 class PollAnswerHandler(Handler[Update, CCT]):
diff --git a/telegram/ext/pollhandler.py b/telegram/ext/pollhandler.py
index 9698185997c..01b16fb7174 100644
--- a/telegram/ext/pollhandler.py
+++ b/telegram/ext/pollhandler.py
@@ -22,7 +22,7 @@
 from telegram import Update
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 
 class PollHandler(Handler[Update, CCT]):
diff --git a/telegram/ext/precheckoutqueryhandler.py b/telegram/ext/precheckoutqueryhandler.py
index 1f2750abbd3..19c25b92980 100644
--- a/telegram/ext/precheckoutqueryhandler.py
+++ b/telegram/ext/precheckoutqueryhandler.py
@@ -22,7 +22,7 @@
 from telegram import Update
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 
 class PreCheckoutQueryHandler(Handler[Update, CCT]):
diff --git a/telegram/ext/regexhandler.py b/telegram/ext/regexhandler.py
index 3fd9c87a285..e4ace39d697 100644
--- a/telegram/ext/regexhandler.py
+++ b/telegram/ext/regexhandler.py
@@ -26,7 +26,7 @@
 from telegram.ext import Filters, MessageHandler
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
-from telegram.utils.types import CCT
+from telegram.ext.utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/shippingqueryhandler.py b/telegram/ext/shippingqueryhandler.py
index 7c36f702d82..116d1ab950a 100644
--- a/telegram/ext/shippingqueryhandler.py
+++ b/telegram/ext/shippingqueryhandler.py
@@ -21,7 +21,7 @@
 
 from telegram import Update
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 
 class ShippingQueryHandler(Handler[Update, CCT]):
diff --git a/telegram/ext/stringcommandhandler.py b/telegram/ext/stringcommandhandler.py
index a4216f052e5..e2d92a726e4 100644
--- a/telegram/ext/stringcommandhandler.py
+++ b/telegram/ext/stringcommandhandler.py
@@ -23,7 +23,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/stringregexhandler.py b/telegram/ext/stringregexhandler.py
index b0465f6fc38..40775cbafac 100644
--- a/telegram/ext/stringregexhandler.py
+++ b/telegram/ext/stringregexhandler.py
@@ -24,7 +24,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 if TYPE_CHECKING:
     from telegram.ext import Dispatcher
diff --git a/telegram/ext/typehandler.py b/telegram/ext/typehandler.py
index 3a745b40b71..071bbf892ae 100644
--- a/telegram/ext/typehandler.py
+++ b/telegram/ext/typehandler.py
@@ -22,7 +22,7 @@
 from telegram.utils.helpers import DefaultValue, DEFAULT_FALSE
 
 from .handler import Handler
-from ..utils.types import CCT
+from .utils.types import CCT
 
 RT = TypeVar('RT')
 UT = TypeVar('UT')
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 127e9950624..f559994c2d1 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -41,19 +41,18 @@
 
 from telegram import Bot, TelegramError
 from telegram.error import InvalidToken, RetryAfter, TimedOut, Unauthorized
-from telegram.ext import Dispatcher, JobQueue, ContextCustomizer
+from telegram.ext import Dispatcher, JobQueue, ContextTypes
 from telegram.utils.deprecate import TelegramDeprecationWarning
 from telegram.utils.helpers import get_signal_name
 from telegram.utils.request import Request
-from telegram.utils.types import CCT, UD, BD, UDM, CDM, CD
+from telegram.ext.utils.types import CCT, UD, CD, BD
 from telegram.ext.utils.webhookhandler import WebhookAppClass, WebhookServer
 
 if TYPE_CHECKING:
-    from collections import defaultdict
     from telegram.ext import BasePersistence, Defaults, CallbackContext
 
 
-class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
+class Updater(Generic[CCT, UD, CD, BD]):
     """
     This class, which employs the :class:`telegram.ext.Dispatcher`, provides a frontend to
     :class:`telegram.Bot` to the programmer, so they can focus on coding the bot. Its purpose is to
@@ -99,10 +98,10 @@ class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
             used).
         defaults (:class:`telegram.ext.Defaults`, optional): An object containing default values to
             be used if not set explicitly in the bot methods.
-        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
-            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+        context_customizer (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
+            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
             ``context`` interface. If not passed, the defaults documented in
-            :class:`telegram.ext.ContextCustomizer` will be used.
+            :class:`telegram.ext.ContextTypes` will be used.
 
     Raises:
         ValueError: If both :attr:`token` and :attr:`bot` are passed or none of them.
@@ -127,7 +126,7 @@ class Updater(Generic[CCT, UD, CD, BD, UDM, CDM]):
 
     @overload
     def __init__(
-        self: 'Updater[CallbackContext, dict, dict, dict, defaultdict, defaultdict]',
+        self: 'Updater[CallbackContext, dict, dict, dict]',
         token: str = None,
         base_url: str = None,
         workers: int = 4,
@@ -145,7 +144,7 @@ def __init__(
 
     @overload
     def __init__(
-        self: 'Updater[CCT, UD, CD, BD, UDM, CDM]',
+        self: 'Updater[CCT, UD, CD, BD]',
         token: str = None,
         base_url: str = None,
         workers: int = 4,
@@ -158,15 +157,15 @@ def __init__(
         defaults: 'Defaults' = None,
         use_context: bool = True,
         base_file_url: str = None,
-        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         ...
 
     @overload
     def __init__(
-        self: 'Updater[CCT, UD, CD, BD, UDM, CDM]',
+        self: 'Updater[CCT, UD, CD, BD]',
         user_sig_handler: Callable = None,
-        dispatcher: Dispatcher[CCT, UD, CD, BD, UDM, CDM] = None,
+        dispatcher: Dispatcher[CCT, UD, CD, BD] = None,
     ):
         ...
 
@@ -185,7 +184,7 @@ def __init__(  # type: ignore[no-untyped-def,misc]
         use_context: bool = True,
         dispatcher=None,
         base_file_url: str = None,
-        context_customizer: ContextCustomizer[CCT, UD, CD, BD, UDM, CDM] = None,
+        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
     ):
 
         if defaults and bot:
diff --git a/telegram/ext/utils/types.py b/telegram/ext/utils/types.py
new file mode 100644
index 00000000000..4769d1fe28a
--- /dev/null
+++ b/telegram/ext/utils/types.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python
+#
+# A library that provides a Python interface to the Telegram Bot API
+# Copyright (C) 2021
+# Leandro Toledo de Souza <devs@python-telegram-bot.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser Public License for more details.
+#
+# You should have received a copy of the GNU Lesser Public License
+# along with this program.  If not, see [http://www.gnu.org/licenses/].
+"""This module contains custom typing aliases."""
+from typing import TypeVar, TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from telegram.ext import CallbackContext  # noqa: F401
+
+CCT = TypeVar('CCT', bound='CallbackContext')
+"""An instance of :class:`telegram.ext.CallbackContext` or a custom subclass."""
+UD = TypeVar('UD')
+"""Type of the user data for a single user."""
+CD = TypeVar('CD')
+"""Type of the chat data for a single user."""
+BD = TypeVar('BD')
+"""Type of the bot data."""
diff --git a/telegram/utils/types.py b/telegram/utils/types.py
index b056dcdf05c..1ffcb2e44ba 100644
--- a/telegram/utils/types.py
+++ b/telegram/utils/types.py
@@ -28,14 +28,11 @@
     Tuple,
     TypeVar,
     Union,
-    Mapping,
-    DefaultDict,
 )
 
 if TYPE_CHECKING:
     from telegram import InputFile  # noqa: F401
     from telegram.utils.helpers import DefaultValue  # noqa: F401
-    from telegram.ext import CallbackContext  # noqa: F401
 
 FileLike = Union[IO, 'InputFile']
 """Either an open file handler or a :class:`telegram.InputFile`."""
@@ -61,21 +58,3 @@
 RT = TypeVar("RT")
 SLT = Union[RT, List[RT], Tuple[RT, ...]]
 """Single instance or list/tuple of instances."""
-
-CCT = TypeVar('CCT', bound='CallbackContext')
-"""An instance of :class:`telegram.ext.CallbackContext` or a custom subclass."""
-
-UD = TypeVar('UD')
-"""Type of the user data for a single user."""
-CD = TypeVar('CD')
-"""Type of the chat data for a single user."""
-BD = TypeVar('BD')
-"""Type of the bot data."""
-UDM = TypeVar('UDM', bound=Mapping)
-"""Type of the user data mapping."""
-CDM = TypeVar('CDM', bound=Mapping)
-"""Type of the chat data mapping."""
-
-DDType = TypeVar('DDType')
-IntDD = DefaultDict[int, DDType]
-"""Type for default dicts with integer keys and generic value."""
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 191c9f607c8..6ec9fc08614 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -32,7 +32,7 @@
     CallbackContext,
     JobQueue,
     BasePersistence,
-    ContextCustomizer,
+    ContextTypes,
 )
 from telegram.ext.dispatcher import run_async, Dispatcher, DispatcherHandlerStop
 from telegram.utils.deprecate import TelegramDeprecationWarning
@@ -918,7 +918,7 @@ class CustomUserMapping(defaultdict):
         class CustomChatMapping(defaultdict):
             pass
 
-        cc = ContextCustomizer(
+        cc = ContextTypes(
             context=CustomContext,
             user_data=int,
             chat_data=float,
@@ -947,7 +947,7 @@ def error_handler(_, context):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextCustomizer(
+            context_customizer=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
@@ -970,7 +970,7 @@ def callback(_, context):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextCustomizer(
+            context_customizer=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
diff --git a/tests/test_jobqueue.py b/tests/test_jobqueue.py
index a665672c208..fa9f5690141 100644
--- a/tests/test_jobqueue.py
+++ b/tests/test_jobqueue.py
@@ -29,7 +29,7 @@
 import pytz
 from apscheduler.schedulers import SchedulerNotRunningError
 from flaky import flaky
-from telegram.ext import JobQueue, Updater, Job, CallbackContext, Dispatcher, ContextCustomizer
+from telegram.ext import JobQueue, Updater, Job, CallbackContext, Dispatcher, ContextTypes
 
 
 class CustomContext(CallbackContext):
@@ -520,7 +520,7 @@ def test_custom_context(self, bot, job_queue):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextCustomizer(
+            context_customizer=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index 6782bd98db9..7e0b71c1356 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -45,7 +45,7 @@
     DictPersistence,
     TypeHandler,
     JobQueue,
-    ContextCustomizer,
+    ContextTypes,
 )
 
 
@@ -1388,7 +1388,7 @@ def job_callback(context):
     @pytest.mark.parametrize('cd', [int, float, complex])
     @pytest.mark.parametrize('bd', [int, float, complex])
     def test_with_context_customizer(self, ud, cd, bd, udm, cdm, singlefile):
-        cc = ContextCustomizer(
+        cc = ContextTypes(
             user_data=ud, chat_data=cd, bot_data=bd, user_data_mapping=udm, chat_data_mapping=cdm
         )
         persistence = PicklePersistence(

From 524ce0dc75afb68496fb542b5f55484c4da8cfc1 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 30 Apr 2021 17:59:28 +0200
Subject: [PATCH 13/31] Fix existing tests

---
 telegram/ext/basepersistence.py | 12 +++++++++---
 tests/test_dispatcher.py        | 28 ++++++++++++++++++----------
 tests/test_persistence.py       | 22 ++++++++++------------
 3 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 436d5125ae7..b4318fb7a00 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -391,7 +391,9 @@ def refresh_user_data(self, user_id: int, user_data: UD) -> None:
             user_id (:obj:`int`): The user ID this :attr:`user_data` is associated with.
             user_data (:class:`telegram.ext.utils.types.UD`): The ``user_data`` of a single user.
         """
-        raise NotImplementedError
+        raise NotImplementedError(
+            'refresh_user_data ist not implemented for this persistence class.'
+        )
 
     def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
@@ -402,7 +404,9 @@ def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
             chat_id (:obj:`int`): The chat ID this :attr:`chat_data` is associated with.
             chat_data (:class:`telegram.ext.utils.types.CD`): The ``chat_data`` of a single chat.
         """
-        raise NotImplementedError
+        raise NotImplementedError(
+            'refresh_chat_data ist not implemented for this persistence class.'
+        )
 
     def refresh_bot_data(self, bot_data: BD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
@@ -412,7 +416,9 @@ def refresh_bot_data(self, bot_data: BD) -> None:
         Args:
             bot_data (:class:`telegram.ext.utils.types.BD`): The ``bot_data``.
         """
-        raise NotImplementedError
+        raise NotImplementedError(
+            'refresh_bot_data ist not implemented for this persistence class.'
+        )
 
     def flush(self) -> None:
         """Will be called by :class:`telegram.ext.Updater` upon receiving a stop signal. Gives the
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 6ec9fc08614..72ab79db92b 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -734,6 +734,15 @@ def get_conversations(self, name):
             def update_conversation(self, name, key, new_state):
                 pass
 
+            def refresh_bot_data(self, bot_data):
+                pass
+
+            def refresh_user_data(self, user_id, user_data):
+                pass
+
+            def refresh_chat_data(self, chat_id, chat_data):
+                pass
+
         def callback(update, context):
             pass
 
@@ -794,6 +803,15 @@ def get_bot_data(self):
             def get_chat_data(self):
                 pass
 
+            def refresh_bot_data(self, bot_data):
+                pass
+
+            def refresh_user_data(self, user_id, user_data):
+                pass
+
+            def refresh_chat_data(self, chat_id, chat_data):
+                pass
+
         def callback(update, context):
             pass
 
@@ -912,26 +930,16 @@ def dummy_callback(*args, **kwargs):
             dp.bot.defaults = None
 
     def test_custom_context_init(self, bot):
-        class CustomUserMapping(defaultdict):
-            pass
-
-        class CustomChatMapping(defaultdict):
-            pass
-
         cc = ContextTypes(
             context=CustomContext,
             user_data=int,
             chat_data=float,
             bot_data=complex,
-            user_data_mapping=CustomUserMapping,
-            chat_data_mapping=CustomChatMapping,
         )
 
         dispatcher = Dispatcher(bot, Queue(), context_customizer=cc)
 
-        assert isinstance(dispatcher.user_data, CustomUserMapping)
         assert isinstance(dispatcher.user_data[1], int)
-        assert isinstance(dispatcher.chat_data, CustomChatMapping)
         assert isinstance(dispatcher.chat_data[1], float)
         assert isinstance(dispatcher.bot_data, complex)
 
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index 7e0b71c1356..bf3886aee58 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -256,8 +256,10 @@ def get_bot_data():
         base_persistence.get_user_data = get_user_data
         base_persistence.get_chat_data = get_chat_data
         base_persistence.get_bot_data = get_bot_data
-        # base_persistence.update_chat_data = lambda x: x
-        # base_persistence.update_user_data = lambda x: x
+        base_persistence.refresh_bot_data = lambda x: x
+        base_persistence.refresh_chat_data = lambda x, y: x
+        base_persistence.refresh_user_data = lambda x, y: x
+
         updater = Updater(bot=bot, persistence=base_persistence, use_context=True)
         dp = updater.dispatcher
 
@@ -362,6 +364,10 @@ def get_bot_data():
         base_persistence.get_user_data = get_user_data
         base_persistence.get_chat_data = get_chat_data
         base_persistence.get_bot_data = get_bot_data
+        base_persistence.refresh_bot_data = lambda x: x
+        base_persistence.refresh_chat_data = lambda x, y: x
+        base_persistence.refresh_user_data = lambda x, y: x
+
         cdp.persistence = base_persistence
         cdp.user_data = user_data
         cdp.chat_data = chat_data
@@ -1382,23 +1388,17 @@ def job_callback(context):
         assert user_data[789] == {'test3': '123'}
 
     @pytest.mark.parametrize('singlefile', [True, False])
-    @pytest.mark.parametrize('udm', [defaultdict, CustomMapping])
-    @pytest.mark.parametrize('cdm', [defaultdict, CustomMapping])
     @pytest.mark.parametrize('ud', [int, float, complex])
     @pytest.mark.parametrize('cd', [int, float, complex])
     @pytest.mark.parametrize('bd', [int, float, complex])
-    def test_with_context_customizer(self, ud, cd, bd, udm, cdm, singlefile):
-        cc = ContextTypes(
-            user_data=ud, chat_data=cd, bot_data=bd, user_data_mapping=udm, chat_data_mapping=cdm
-        )
+    def test_with_context_customizer(self, ud, cd, bd, singlefile):
+        cc = ContextTypes(user_data=ud, chat_data=cd, bot_data=bd)
         persistence = PicklePersistence(
             'pickletest', single_file=singlefile, context_customizer=cc
         )
 
-        assert isinstance(persistence.get_user_data(), udm)
         assert isinstance(persistence.get_user_data()[1], ud)
         assert persistence.get_user_data()[1] == 0
-        assert isinstance(persistence.get_chat_data(), cdm)
         assert isinstance(persistence.get_chat_data()[1], cd)
         assert persistence.get_chat_data()[1] == 0
         assert isinstance(persistence.get_bot_data(), bd)
@@ -1417,10 +1417,8 @@ def test_with_context_customizer(self, ud, cd, bd, udm, cdm, singlefile):
         persistence = PicklePersistence(
             'pickletest', single_file=singlefile, context_customizer=cc
         )
-        assert isinstance(persistence.get_user_data(), udm)
         assert isinstance(persistence.get_user_data()[1], ud)
         assert persistence.get_user_data()[1] == 1
-        assert isinstance(persistence.get_chat_data(), cdm)
         assert isinstance(persistence.get_chat_data()[1], cd)
         assert persistence.get_chat_data()[1] == 1
         assert isinstance(persistence.get_bot_data(), bd)

From a0a65dcf041db52afbbf0ae346e026eaea5aab09 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 30 Apr 2021 19:21:33 +0200
Subject: [PATCH 14/31] Add new tests

---
 telegram/ext/basepersistence.py |   3 +-
 tests/test_callbackcontext.py   |   4 +
 tests/test_contexttypes.py      |  47 ++++++
 tests/test_persistence.py       | 254 +++++++++++++++++---------------
 4 files changed, 189 insertions(+), 119 deletions(-)
 create mode 100644 tests/test_contexttypes.py

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index b4318fb7a00..900fa98ef2a 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -48,7 +48,8 @@ class BasePersistence(Generic[UD, CD, BD], ABC):
     * :meth:`flush`
 
     If you don't actually need one of those methods, a simple ``pass`` is enough. For example, if
-    ``store_bot_data=False``, you don't need :meth:`get_bot_data` and :meth:`update_bot_data`.
+    ``store_bot_data=False``, you don't need :meth:`get_bot_data`, :meth:`update_bot_data` or
+    :meth:`refresh_bot_data`.
 
     Warning:
         Persistence will try to replace :class:`telegram.Bot` instances by :attr:`REPLACED_BOT` and
diff --git a/tests/test_callbackcontext.py b/tests/test_callbackcontext.py
index 8018b0ce0d4..8c114a3e200 100644
--- a/tests/test_callbackcontext.py
+++ b/tests/test_callbackcontext.py
@@ -21,6 +21,10 @@
 from telegram import Update, Message, Chat, User, TelegramError
 from telegram.ext import CallbackContext
 
+"""
+CallbackContext.refresh_data is tested in TestBasePersistence
+"""
+
 
 class TestCallbackContext:
     def test_non_context_dp(self, dp):
diff --git a/tests/test_contexttypes.py b/tests/test_contexttypes.py
new file mode 100644
index 00000000000..a6cfeb587b6
--- /dev/null
+++ b/tests/test_contexttypes.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+#
+# A library that provides a Python interface to the Telegram Bot API
+# Copyright (C) 2021
+# Leandro Toledo de Souza <devs@python-telegram-bot.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser Public License for more details.
+#
+# You should have received a copy of the GNU Lesser Public License
+# along with this program.  If not, see [http://www.gnu.org/licenses/].
+import pytest
+
+from telegram.ext import ContextTypes, CallbackContext
+
+
+class SubClass(CallbackContext):
+    pass
+
+
+class TestContextTypes:
+    def test_data_init(self):
+        ct = ContextTypes(SubClass, int, float, bool)
+        assert ct.context is SubClass
+        assert ct.bot_data is int
+        assert ct.chat_data is float
+        assert ct.user_data is bool
+
+        with pytest.raises(ValueError, match='subclass of CallbackContext'):
+            ContextTypes(context=bool)
+
+    def test_data_assignment(self):
+        ct = ContextTypes()
+
+        with pytest.raises(AttributeError):
+            ct.bot_data = bool
+        with pytest.raises(AttributeError):
+            ct.user_data = bool
+        with pytest.raises(AttributeError):
+            ct.chat_data = bool
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index bf3886aee58..5f56b73ef10 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -170,6 +170,12 @@ def job_queue(bot):
 
 
 class TestBasePersistence:
+    test_flag = False
+
+    @pytest.fixture(scope='function', autouse=True)
+    def reset(self):
+        self.test_flag = False
+
     def test_creation(self, base_persistence):
         assert base_persistence.store_chat_data
         assert base_persistence.store_user_data
@@ -186,6 +192,14 @@ def test_abstract_methods(self):
         ):
             BasePersistence()
 
+    def test_not_implemented_errors(self, base_persistence):
+        with pytest.raises(NotImplementedError, match='refresh_bot_data'):
+            base_persistence.refresh_bot_data(True)
+        with pytest.raises(NotImplementedError, match='refresh_chat_data'):
+            base_persistence.refresh_chat_data(1, True)
+        with pytest.raises(NotImplementedError, match='refresh_user_data'):
+            base_persistence.refresh_user_data(1, True)
+
     def test_implementation(self, updater, base_persistence):
         dp = updater.dispatcher
         assert dp.persistence == base_persistence
@@ -241,116 +255,17 @@ def get_bot_data():
         u.dispatcher.chat_data[442233]['test5'] = 'test6'
         assert u.dispatcher.chat_data[442233]['test5'] == 'test6'
 
+    @pytest.mark.parametrize('run_async', [True, False], ids=['synchronous', 'run_async'])
     def test_dispatcher_integration_handlers(
-        self, caplog, bot, base_persistence, chat_data, user_data, bot_data
-    ):
-        def get_user_data():
-            return user_data
-
-        def get_chat_data():
-            return chat_data
-
-        def get_bot_data():
-            return bot_data
-
-        base_persistence.get_user_data = get_user_data
-        base_persistence.get_chat_data = get_chat_data
-        base_persistence.get_bot_data = get_bot_data
-        base_persistence.refresh_bot_data = lambda x: x
-        base_persistence.refresh_chat_data = lambda x, y: x
-        base_persistence.refresh_user_data = lambda x, y: x
-
-        updater = Updater(bot=bot, persistence=base_persistence, use_context=True)
-        dp = updater.dispatcher
-
-        def callback_known_user(update, context):
-            if not context.user_data['test1'] == 'test2':
-                pytest.fail('user_data corrupt')
-            if not context.bot_data == bot_data:
-                pytest.fail('bot_data corrupt')
-
-        def callback_known_chat(update, context):
-            if not context.chat_data['test3'] == 'test4':
-                pytest.fail('chat_data corrupt')
-            if not context.bot_data == bot_data:
-                pytest.fail('bot_data corrupt')
-
-        def callback_unknown_user_or_chat(update, context):
-            if not context.user_data == {}:
-                pytest.fail('user_data corrupt')
-            if not context.chat_data == {}:
-                pytest.fail('chat_data corrupt')
-            if not context.bot_data == bot_data:
-                pytest.fail('bot_data corrupt')
-            context.user_data[1] = 'test7'
-            context.chat_data[2] = 'test8'
-            context.bot_data['test0'] = 'test0'
-
-        known_user = MessageHandler(
-            Filters.user(user_id=12345),
-            callback_known_user,
-            pass_chat_data=True,
-            pass_user_data=True,
-        )
-        known_chat = MessageHandler(
-            Filters.chat(chat_id=-67890),
-            callback_known_chat,
-            pass_chat_data=True,
-            pass_user_data=True,
-        )
-        unknown = MessageHandler(
-            Filters.all, callback_unknown_user_or_chat, pass_chat_data=True, pass_user_data=True
-        )
-        dp.add_handler(known_user)
-        dp.add_handler(known_chat)
-        dp.add_handler(unknown)
-        user1 = User(id=12345, first_name='test user', is_bot=False)
-        user2 = User(id=54321, first_name='test user', is_bot=False)
-        chat1 = Chat(id=-67890, type='group')
-        chat2 = Chat(id=-987654, type='group')
-        m = Message(1, None, chat2, from_user=user1)
-        u = Update(0, m)
-        with caplog.at_level(logging.ERROR):
-            dp.process_update(u)
-        rec = caplog.records[-1]
-        assert rec.getMessage() == 'No error handlers are registered, logging exception.'
-        assert rec.levelname == 'ERROR'
-        rec = caplog.records[-2]
-        assert rec.getMessage() == 'No error handlers are registered, logging exception.'
-        assert rec.levelname == 'ERROR'
-        rec = caplog.records[-3]
-        assert rec.getMessage() == 'No error handlers are registered, logging exception.'
-        assert rec.levelname == 'ERROR'
-        m.from_user = user2
-        m.chat = chat1
-        u = Update(1, m)
-        dp.process_update(u)
-        m.chat = chat2
-        u = Update(2, m)
-
-        def save_bot_data(data):
-            if 'test0' not in data:
-                pytest.fail()
-
-        def save_chat_data(data):
-            if -987654 not in data:
-                pytest.fail()
-
-        def save_user_data(data):
-            if 54321 not in data:
-                pytest.fail()
-
-        base_persistence.update_chat_data = save_chat_data
-        base_persistence.update_user_data = save_user_data
-        base_persistence.update_bot_data = save_bot_data
-        dp.process_update(u)
-
-        assert dp.user_data[54321][1] == 'test7'
-        assert dp.chat_data[-987654][2] == 'test8'
-        assert dp.bot_data['test0'] == 'test0'
-
-    def test_dispatcher_integration_handlers_run_async(
-        self, cdp, caplog, bot, base_persistence, chat_data, user_data, bot_data
+        self,
+        cdp,
+        caplog,
+        bot,
+        base_persistence,
+        chat_data,
+        user_data,
+        bot_data,
+        run_async,
     ):
         def get_user_data():
             return user_data
@@ -401,21 +316,21 @@ def callback_unknown_user_or_chat(update, context):
             callback_known_user,
             pass_chat_data=True,
             pass_user_data=True,
-            run_async=True,
+            run_async=run_async,
         )
         known_chat = MessageHandler(
             Filters.chat(chat_id=-67890),
             callback_known_chat,
             pass_chat_data=True,
             pass_user_data=True,
-            run_async=True,
+            run_async=run_async,
         )
         unknown = MessageHandler(
             Filters.all,
             callback_unknown_user_or_chat,
             pass_chat_data=True,
             pass_user_data=True,
-            run_async=True,
+            run_async=run_async,
         )
         cdp.add_handler(known_user)
         cdp.add_handler(known_chat)
@@ -430,12 +345,16 @@ def callback_unknown_user_or_chat(update, context):
             cdp.process_update(u)
 
         sleep(0.1)
-        rec = caplog.records[-1]
-        assert rec.getMessage() == 'No error handlers are registered, logging exception.'
-        assert rec.levelname == 'ERROR'
-        rec = caplog.records[-2]
-        assert rec.getMessage() == 'No error handlers are registered, logging exception.'
-        assert rec.levelname == 'ERROR'
+
+        # In base_persistence.update_*_data we currently just raise NotImplementedError
+        # This makes sure that this doesn't break the processing and is properly handled by
+        # the error handler
+        # We override `update_*_data` further below.
+        assert len(caplog.records) == 3
+        for rec in caplog.records:
+            assert rec.getMessage() == 'No error handlers are registered, logging exception.'
+            assert rec.levelname == 'ERROR'
+
         m.from_user = user2
         m.chat = chat1
         u = Update(1, m)
@@ -466,6 +385,105 @@ def save_user_data(data):
         assert cdp.chat_data[-987654][2] == 'test8'
         assert cdp.bot_data['test0'] == 'test0'
 
+    @pytest.mark.parametrize(
+        'store_user_data', [True, False], ids=['store_user_data-True', 'store_user_data-False']
+    )
+    @pytest.mark.parametrize(
+        'store_chat_data', [True, False], ids=['store_chat_data-True', 'store_chat_data-False']
+    )
+    @pytest.mark.parametrize(
+        'store_bot_data', [True, False], ids=['store_bot_data-True', 'store_bot_data-False']
+    )
+    @pytest.mark.parametrize('run_async', [True, False], ids=['synchronous', 'run_async'])
+    def test_persistence_dispatcher_integration_refresh_data(
+        self,
+        cdp,
+        base_persistence,
+        chat_data,
+        bot_data,
+        user_data,
+        store_bot_data,
+        store_chat_data,
+        store_user_data,
+        run_async,
+    ):
+        base_persistence.refresh_bot_data = lambda x: x.setdefault(
+            'refreshed', x.get('refreshed', 0) + 1
+        )
+        # x is the user/chat_id
+        base_persistence.refresh_chat_data = lambda x, y: y.setdefault('refreshed', x)
+        base_persistence.refresh_user_data = lambda x, y: y.setdefault('refreshed', x)
+        base_persistence.store_bot_data = store_bot_data
+        base_persistence.store_chat_data = store_chat_data
+        base_persistence.store_user_data = store_user_data
+        cdp.persistence = base_persistence
+
+        self.test_flag = True
+
+        def callback_with_user_and_chat(update, context):
+            if store_user_data:
+                if context.user_data.get('refreshed') != update.effective_user.id:
+                    self.test_flag = 'user_data was not refreshed'
+            else:
+                if 'refreshed' in context.user_data:
+                    self.test_flag = 'user_data was wrongly refreshed'
+            if store_chat_data:
+                if context.chat_data.get('refreshed') != update.effective_chat.id:
+                    self.test_flag = 'chat_data was not refreshed'
+            else:
+                if 'refreshed' in context.chat_data:
+                    self.test_flag = 'chat_data was wrongly refreshed'
+            if store_bot_data:
+                if context.bot_data.get('refreshed') != 1:
+                    self.test_flag = 'bot_data was not refreshed'
+            else:
+                if 'refreshed' in context.bot_data:
+                    self.test_flag = 'bot_data was wrongly refreshed'
+
+        def callback_without_user_and_chat(_, context):
+            if store_bot_data:
+                if context.bot_data.get('refreshed') != 1:
+                    self.test_flag = 'bot_data was not refreshed'
+            else:
+                if 'refreshed' in context.bot_data:
+                    self.test_flag = 'bot_data was wrongly refreshed'
+
+        with_user_and_chat = MessageHandler(
+            Filters.user(user_id=12345),
+            callback_with_user_and_chat,
+            pass_chat_data=True,
+            pass_user_data=True,
+            run_async=run_async,
+        )
+        without_user_and_chat = MessageHandler(
+            Filters.all,
+            callback_without_user_and_chat,
+            pass_chat_data=True,
+            pass_user_data=True,
+            run_async=run_async,
+        )
+        cdp.add_handler(with_user_and_chat)
+        cdp.add_handler(without_user_and_chat)
+        user = User(id=12345, first_name='test user', is_bot=False)
+        chat = Chat(id=-987654, type='group')
+        m = Message(1, None, chat, from_user=user)
+
+        # has user and chat
+        u = Update(0, m)
+        cdp.process_update(u)
+
+        assert self.test_flag is True
+
+        # has neither user nor hat
+        m.from_user = None
+        m.chat = None
+        u = Update(1, m)
+        cdp.process_update(u)
+
+        assert self.test_flag is True
+
+        sleep(0.1)
+
     def test_persistence_dispatcher_arbitrary_update_types(self, dp, base_persistence, caplog):
         # Updates used with TypeHandler doesn't necessarily have the proper attributes for
         # persistence, makes sure it works anyways

From 86f3a1308e383cc22bde956ca40b9237890d8d9e Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sat, 1 May 2021 11:55:32 +0200
Subject: [PATCH 15/31] Update docs & add some versioning directives

---
 telegram/ext/contexttypes.py      |  2 ++
 telegram/ext/dispatcher.py        | 34 ++++++++++++-----------
 telegram/ext/jobqueue.py          |  4 +--
 telegram/ext/picklepersistence.py | 46 ++++++++++++++++---------------
 telegram/ext/updater.py           | 14 ++++++----
 tests/test_dispatcher.py          |  6 ++--
 tests/test_jobqueue.py            |  2 +-
 tests/test_persistence.py         | 10 ++-----
 tests/test_updater.py             |  2 +-
 9 files changed, 62 insertions(+), 58 deletions(-)

diff --git a/telegram/ext/contexttypes.py b/telegram/ext/contexttypes.py
index 10286e40c2e..f39f3ebce36 100644
--- a/telegram/ext/contexttypes.py
+++ b/telegram/ext/contexttypes.py
@@ -29,6 +29,8 @@ class ContextTypes(Generic[CCT, UD, CD, BD]):
     Convenience class to gather customizable types of the :class:`telegram.ext.CallbackContext`
     interface.
 
+    .. versionadded:: 13.6
+
     Args:
         context (:obj:`type`, optional): Determines the type of the ``context`` argument of all
             (error-)handler callbacks and job callbacks. Must be a subclass of
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index faf060908fd..e0e613f5d9e 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -134,10 +134,12 @@ class Dispatcher(Generic[CCT, UD, CD, BD]):
         use_context (:obj:`bool`, optional): If set to :obj:`True` uses the context based callback
             API (ignored if `dispatcher` argument is used). Defaults to :obj:`True`.
             **New users**: set this to :obj:`True`.
-        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
-            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+        context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
+            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
             ``context`` interface. If not passed, the defaults documented in
-            :class:`telegram.ext.ContextCustomizer` will be used.
+            :class:`telegram.ext.ContextTypes` will be used.
+
+            .. versionadded:: 13.6
 
     Attributes:
         bot (:class:`telegram.Bot`): The bot object that should be passed to the handlers.
@@ -151,9 +153,11 @@ class Dispatcher(Generic[CCT, UD, CD, BD]):
         bot_data (:obj:`dict`): A dictionary handlers can use to store data for the bot.
         persistence (:class:`telegram.ext.BasePersistence`): Optional. The persistence class to
             store data that should be persistent over restarts.
-        context_customizer (:class:`telegram.ext.ContextTypes`): Container for the types used
+        context_types (:class:`telegram.ext.ContextTypes`): Container for the types used
             in the ``context`` interface.
 
+            .. versionadded:: 13.6
+
     """
 
     __singleton_lock = Lock()
@@ -184,7 +188,7 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
+        context_types: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         ...
 
@@ -197,16 +201,14 @@ def __init__(
         job_queue: 'JobQueue' = None,
         persistence: BasePersistence = None,
         use_context: bool = True,
-        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
+        context_types: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         self.bot = bot
         self.update_queue = update_queue
         self.job_queue = job_queue
         self.workers = workers
         self.use_context = use_context
-        self.context_customizer = cast(
-            ContextTypes[CCT, UD, CD, BD], context_customizer or ContextTypes()
-        )
+        self.context_types = cast(ContextTypes[CCT, UD, CD, BD], context_types or ContextTypes())
 
         if not use_context:
             warnings.warn(
@@ -220,9 +222,9 @@ def __init__(
                 'Asynchronous callbacks can not be processed without at least one worker thread.'
             )
 
-        self.user_data: DefaultDict[int, UD] = defaultdict(self.context_customizer.user_data)
-        self.chat_data: DefaultDict[int, CD] = defaultdict(self.context_customizer.chat_data)
-        self.bot_data = self.context_customizer.bot_data()
+        self.user_data: DefaultDict[int, UD] = defaultdict(self.context_types.user_data)
+        self.chat_data: DefaultDict[int, CD] = defaultdict(self.context_types.chat_data)
+        self.bot_data = self.context_types.bot_data()
         self.persistence: Optional[BasePersistence] = None
         self._update_persistence_lock = Lock()
         if persistence:
@@ -240,9 +242,9 @@ def __init__(
                     raise ValueError("chat_data must be of type defaultdict")
             if self.persistence.store_bot_data:
                 self.bot_data = self.persistence.get_bot_data()
-                if not isinstance(self.bot_data, self.context_customizer.bot_data):
+                if not isinstance(self.bot_data, self.context_types.bot_data):
                     raise ValueError(
-                        f"bot_data must be of type {self.context_customizer.bot_data.__name__}"
+                        f"bot_data must be of type {self.context_types.bot_data.__name__}"
                     )
 
         else:
@@ -497,7 +499,7 @@ def process_update(self, update: object) -> None:
                     check = handler.check_update(update)
                     if check is not None and check is not False:
                         if not context and self.use_context:
-                            context = self.context_customizer.context.from_update(update, self)
+                            context = self.context_types.context.from_update(update, self)
                             context.refresh_data()
                         handled = True
                         sync_modes.append(handler.run_async)
@@ -735,7 +737,7 @@ def dispatch_error(
         if self.error_handlers:
             for callback, run_async in self.error_handlers.items():  # pylint: disable=W0621
                 if self.use_context:
-                    context = self.context_customizer.context.from_error(
+                    context = self.context_types.context.from_error(
                         update, error, self, async_args=async_args, async_kwargs=async_kwargs
                     )
                     if run_async:
diff --git a/telegram/ext/jobqueue.py b/telegram/ext/jobqueue.py
index 6b88bda65c8..1ff8e68a1ef 100644
--- a/telegram/ext/jobqueue.py
+++ b/telegram/ext/jobqueue.py
@@ -71,7 +71,7 @@ def aps_log_filter(record):  # type: ignore
 
     def _build_args(self, job: 'Job') -> List[Union[CallbackContext, 'Bot', 'Job']]:
         if self._dispatcher.use_context:
-            return [self._dispatcher.context_customizer.context.from_job(job, self._dispatcher)]
+            return [self._dispatcher.context_types.context.from_job(job, self._dispatcher)]
         return [self._dispatcher.bot, job]
 
     def _tz_now(self) -> datetime.datetime:
@@ -569,7 +569,7 @@ def run(self, dispatcher: 'Dispatcher') -> None:
         """Executes the callback function independently of the jobs schedule."""
         try:
             if dispatcher.use_context:
-                self.callback(dispatcher.context_customizer.context.from_job(self, dispatcher))
+                self.callback(dispatcher.context_types.context.from_job(self, dispatcher))
             else:
                 self.callback(dispatcher.bot, self)  # type: ignore[arg-type,call-arg]
         except Exception as exc:
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index 3586c386210..2a1eeb3b9fa 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -63,10 +63,12 @@ class PicklePersistence(BasePersistence[UD, CD, BD]):
             :meth:`flush` is called and keep data in memory until that happens. When
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
-        context_customizer (:class:`telegram.ext.ContextCustomizer`, optional): Pass an instance
-            of :class:`telegram.ext.ContextCustomizer` to customize the the types used in the
+        context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
+            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
             ``context`` interface. If not passed, the defaults documented in
-            :class:`telegram.ext.ContextCustomizer` will be used.
+            :class:`telegram.ext.ContextTypes` will be used.
+
+            .. versionadded:: 13.6
 
     Attributes:
         filename (:obj:`str`): The filename for storing the pickle files. When :attr:`single_file`
@@ -84,8 +86,10 @@ class PicklePersistence(BasePersistence[UD, CD, BD]):
             :meth:`flush` is called and keep data in memory until that happens. When
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
-        context_customizer (:class:`telegram.ext.ContextTypes`): Container for the types used
+        context_types (:class:`telegram.ext.ContextTypes`): Container for the types used
             in the ``context`` interface.
+
+            .. versionadded:: 13.6
     """
 
     @overload
@@ -109,7 +113,7 @@ def __init__(
         store_bot_data: bool = True,
         single_file: bool = True,
         on_flush: bool = False,
-        context_customizer: ContextTypes[Any, UD, CD, BD] = None,
+        context_types: ContextTypes[Any, UD, CD, BD] = None,
     ):
         ...
 
@@ -121,7 +125,7 @@ def __init__(
         store_bot_data: bool = True,
         single_file: bool = True,
         on_flush: bool = False,
-        context_customizer: ContextTypes[Any, UD, CD, BD] = None,
+        context_types: ContextTypes[Any, UD, CD, BD] = None,
     ):
         super().__init__(
             store_user_data=store_user_data,
@@ -135,25 +139,23 @@ def __init__(
         self.chat_data: Optional[DefaultDict[int, CD]] = None
         self.bot_data: Optional[BD] = None
         self.conversations: Optional[Dict[str, Dict[Tuple, object]]] = None
-        self.context_customizer = cast(
-            ContextTypes[Any, UD, CD, BD], context_customizer or ContextTypes()
-        )
+        self.context_types = cast(ContextTypes[Any, UD, CD, BD], context_types or ContextTypes())
 
     def load_singlefile(self) -> None:
         try:
             filename = self.filename
             with open(self.filename, "rb") as file:
                 data = pickle.load(file)
-                self.user_data = defaultdict(self.context_customizer.user_data, data['user_data'])
-                self.chat_data = defaultdict(self.context_customizer.chat_data, data['chat_data'])
+                self.user_data = defaultdict(self.context_types.user_data, data['user_data'])
+                self.chat_data = defaultdict(self.context_types.chat_data, data['chat_data'])
                 # For backwards compatibility with files not containing bot data
-                self.bot_data = data.get('bot_data', self.context_customizer.bot_data())
+                self.bot_data = data.get('bot_data', self.context_types.bot_data())
                 self.conversations = data['conversations']
         except OSError:
             self.conversations = {}
-            self.user_data = defaultdict(self.context_customizer.user_data)
-            self.chat_data = defaultdict(self.context_customizer.chat_data)
-            self.bot_data = self.context_customizer.bot_data()
+            self.user_data = defaultdict(self.context_types.user_data)
+            self.chat_data = defaultdict(self.context_types.chat_data)
+            self.bot_data = self.context_types.bot_data()
         except pickle.UnpicklingError as exc:
             raise TypeError(f"File {filename} does not contain valid pickle data") from exc
         except Exception as exc:
@@ -198,9 +200,9 @@ def get_user_data(self) -> DefaultDict[int, UD]:
             filename = f"{self.filename}_user_data"
             data = self.load_file(filename)
             if not data:
-                data = defaultdict(self.context_customizer.user_data)
+                data = defaultdict(self.context_types.user_data)
             else:
-                data = defaultdict(self.context_customizer.user_data, data)
+                data = defaultdict(self.context_types.user_data, data)
             self.user_data = data
         else:
             self.load_singlefile()
@@ -218,9 +220,9 @@ def get_chat_data(self) -> DefaultDict[int, CD]:
             filename = f"{self.filename}_chat_data"
             data = self.load_file(filename)
             if not data:
-                data = defaultdict(self.context_customizer.chat_data)
+                data = defaultdict(self.context_types.chat_data)
             else:
-                data = defaultdict(self.context_customizer.chat_data, data)
+                data = defaultdict(self.context_types.chat_data, data)
             self.chat_data = data
         else:
             self.load_singlefile()
@@ -239,7 +241,7 @@ def get_bot_data(self) -> BD:
             filename = f"{self.filename}_bot_data"
             data = self.load_file(filename)
             if not data:
-                data = self.context_customizer.bot_data()
+                data = self.context_types.bot_data()
             self.bot_data = data
         else:
             self.load_singlefile()
@@ -298,7 +300,7 @@ def update_user_data(self, user_id: int, data: UD) -> None:
                 :attr:`telegram.ext.dispatcher.user_data` ``[user_id]``.
         """
         if self.user_data is None:
-            self.user_data = defaultdict(self.context_customizer.user_data)
+            self.user_data = defaultdict(self.context_types.user_data)
         if self.user_data.get(user_id) == data:
             return
         self.user_data[user_id] = data
@@ -318,7 +320,7 @@ def update_chat_data(self, chat_id: int, data: CD) -> None:
                 :attr:`telegram.ext.dispatcher.chat_data` ``[chat_id]``.
         """
         if self.chat_data is None:
-            self.chat_data = defaultdict(self.context_customizer.chat_data)
+            self.chat_data = defaultdict(self.context_types.chat_data)
         if self.chat_data.get(chat_id) == data:
             return
         self.chat_data[chat_id] = data
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index f559994c2d1..24acec454b3 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -98,11 +98,13 @@ class Updater(Generic[CCT, UD, CD, BD]):
             used).
         defaults (:class:`telegram.ext.Defaults`, optional): An object containing default values to
             be used if not set explicitly in the bot methods.
-        context_customizer (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
+        context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
             of :class:`telegram.ext.ContextTypes` to customize the the types used in the
             ``context`` interface. If not passed, the defaults documented in
             :class:`telegram.ext.ContextTypes` will be used.
 
+            .. versionadded:: 13.6
+
     Raises:
         ValueError: If both :attr:`token` and :attr:`bot` are passed or none of them.
 
@@ -157,7 +159,7 @@ def __init__(
         defaults: 'Defaults' = None,
         use_context: bool = True,
         base_file_url: str = None,
-        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
+        context_types: ContextTypes[CCT, UD, CD, BD] = None,
     ):
         ...
 
@@ -184,7 +186,7 @@ def __init__(  # type: ignore[no-untyped-def,misc]
         use_context: bool = True,
         dispatcher=None,
         base_file_url: str = None,
-        context_customizer: ContextTypes[CCT, UD, CD, BD] = None,
+        context_types: ContextTypes[CCT, UD, CD, BD] = None,
     ):
 
         if defaults and bot:
@@ -209,8 +211,8 @@ def __init__(  # type: ignore[no-untyped-def,misc]
                 raise ValueError('`dispatcher` and `persistence` are mutually exclusive')
             if use_context != dispatcher.use_context:
                 raise ValueError('`dispatcher` and `use_context` are mutually exclusive')
-            if context_customizer is not None:
-                raise ValueError('`dispatcher` and `context_customizer` are mutually exclusive')
+            if context_types is not None:
+                raise ValueError('`dispatcher` and `context_types` are mutually exclusive')
             if workers is not None:
                 raise ValueError('`dispatcher` and `workers` are mutually exclusive')
 
@@ -259,7 +261,7 @@ def __init__(  # type: ignore[no-untyped-def,misc]
                 exception_event=self.__exception_event,
                 persistence=persistence,
                 use_context=use_context,
-                context_customizer=context_customizer,
+                context_types=context_types,
             )
             self.job_queue.set_dispatcher(self.dispatcher)
         else:
diff --git a/tests/test_dispatcher.py b/tests/test_dispatcher.py
index 72ab79db92b..ba07be47403 100644
--- a/tests/test_dispatcher.py
+++ b/tests/test_dispatcher.py
@@ -937,7 +937,7 @@ def test_custom_context_init(self, bot):
             bot_data=complex,
         )
 
-        dispatcher = Dispatcher(bot, Queue(), context_customizer=cc)
+        dispatcher = Dispatcher(bot, Queue(), context_types=cc)
 
         assert isinstance(dispatcher.user_data[1], int)
         assert isinstance(dispatcher.chat_data[1], float)
@@ -955,7 +955,7 @@ def error_handler(_, context):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextTypes(
+            context_types=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
@@ -978,7 +978,7 @@ def callback(_, context):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextTypes(
+            context_types=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
diff --git a/tests/test_jobqueue.py b/tests/test_jobqueue.py
index fa9f5690141..c3c888d761a 100644
--- a/tests/test_jobqueue.py
+++ b/tests/test_jobqueue.py
@@ -520,7 +520,7 @@ def test_custom_context(self, bot, job_queue):
         dispatcher = Dispatcher(
             bot,
             Queue(),
-            context_customizer=ContextTypes(
+            context_types=ContextTypes(
                 context=CustomContext, bot_data=int, user_data=float, chat_data=complex
             ),
         )
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index 5f56b73ef10..8b9f49a7e40 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -1409,11 +1409,9 @@ def job_callback(context):
     @pytest.mark.parametrize('ud', [int, float, complex])
     @pytest.mark.parametrize('cd', [int, float, complex])
     @pytest.mark.parametrize('bd', [int, float, complex])
-    def test_with_context_customizer(self, ud, cd, bd, singlefile):
+    def test_with_context_types(self, ud, cd, bd, singlefile):
         cc = ContextTypes(user_data=ud, chat_data=cd, bot_data=bd)
-        persistence = PicklePersistence(
-            'pickletest', single_file=singlefile, context_customizer=cc
-        )
+        persistence = PicklePersistence('pickletest', single_file=singlefile, context_types=cc)
 
         assert isinstance(persistence.get_user_data()[1], ud)
         assert persistence.get_user_data()[1] == 0
@@ -1432,9 +1430,7 @@ def test_with_context_customizer(self, ud, cd, bd, singlefile):
         assert persistence.get_bot_data() == 1
 
         persistence.flush()
-        persistence = PicklePersistence(
-            'pickletest', single_file=singlefile, context_customizer=cc
-        )
+        persistence = PicklePersistence('pickletest', single_file=singlefile, context_types=cc)
         assert isinstance(persistence.get_user_data()[1], ud)
         assert persistence.get_user_data()[1] == 1
         assert isinstance(persistence.get_chat_data()[1], cd)
diff --git a/tests/test_updater.py b/tests/test_updater.py
index 030436e3b59..9a1f9a53baa 100644
--- a/tests/test_updater.py
+++ b/tests/test_updater.py
@@ -644,7 +644,7 @@ def test_mutual_exclude_use_context_dispatcher(self):
     def test_mutual_exclude_custom_context_dispatcher(self):
         dispatcher = Dispatcher(None, None)
         with pytest.raises(ValueError):
-            Updater(dispatcher=dispatcher, context_customizer=True)
+            Updater(dispatcher=dispatcher, context_types=True)
 
     def test_defaults_warning(self, bot):
         with pytest.warns(TelegramDeprecationWarning, match='no effect when a Bot is passed'):

From 5dc7e1822f5bf97ed6558705879eda2d3bc47980 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Wed, 5 May 2021 21:27:29 +0200
Subject: [PATCH 16/31] Annotation fix

---
 telegram/ext/basepersistence.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 900fa98ef2a..5c8055295f2 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -20,7 +20,7 @@
 import warnings
 from abc import ABC, abstractmethod
 from copy import copy
-from typing import Dict, Optional, Tuple, cast, ClassVar, Generic, Mapping, DefaultDict
+from typing import Dict, Optional, Tuple, cast, ClassVar, Generic, DefaultDict
 
 from telegram import Bot
 
@@ -91,10 +91,10 @@ def __new__(
         update_chat_data = instance.update_chat_data
         update_bot_data = instance.update_bot_data
 
-        def get_user_data_insert_bot() -> Mapping[int, UD]:
+        def get_user_data_insert_bot() -> DefaultDict[int, UD]:
             return instance.insert_bot(get_user_data())
 
-        def get_chat_data_insert_bot() -> Mapping[int, CD]:
+        def get_chat_data_insert_bot() -> DefaultDict[int, CD]:
             return instance.insert_bot(get_chat_data())
 
         def get_bot_data_insert_bot() -> BD:

From 39d1e781f1178dbc98418fd0d45b5d7fafe3397a Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Wed, 5 May 2021 21:35:14 +0200
Subject: [PATCH 17/31] Only specify major version of GH Actions

---
 .github/workflows/test.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ba3c919eff0..f9dbe68851d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -60,7 +60,7 @@ jobs:
         shell: bash --noprofile --norc {0}
 
       - name: Submit coverage
-        uses: codecov/codecov-action@v1.0.13
+        uses: codecov/codecov-action@v1
         with:
           env_vars: OS,PYTHON
           name: ${{ matrix.os }}-${{ matrix.python-version }}
@@ -79,7 +79,7 @@ jobs:
         run:
           git submodule update --init --recursive
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -108,7 +108,7 @@ jobs:
         run:
           git submodule update --init --recursive
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v2
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies

From 6753bcfcf192646156d6294ef4049c56e7558c84 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Mon, 10 May 2021 11:37:09 +0200
Subject: [PATCH 18/31] Slight typing improvements

---
 telegram/ext/callbackcontext.py | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
index a0cb08946c5..465f19bb6d8 100644
--- a/telegram/ext/callbackcontext.py
+++ b/telegram/ext/callbackcontext.py
@@ -19,7 +19,19 @@
 # pylint: disable=R0201
 """This module contains the CallbackContext class."""
 from queue import Queue
-from typing import TYPE_CHECKING, Dict, List, Match, NoReturn, Optional, Tuple, Union, Generic
+from typing import (
+    TYPE_CHECKING,
+    Dict,
+    List,
+    Match,
+    NoReturn,
+    Optional,
+    Tuple,
+    Union,
+    Generic,
+    Type,
+    TypeVar,
+)
 
 from telegram import Update
 from telegram.ext.utils.types import UD, CD, BD
@@ -28,6 +40,8 @@
     from telegram import Bot
     from telegram.ext import Dispatcher, Job, JobQueue
 
+CC = TypeVar('CC', bound='CallbackContext')
+
 
 class CallbackContext(Generic[UD, CD, BD]):
     """
@@ -172,13 +186,13 @@ def refresh_data(self) -> None:
 
     @classmethod
     def from_error(
-        cls,
+        cls: Type[CC],
         update: object,
         error: Exception,
         dispatcher: 'Dispatcher',
         async_args: Union[List, Tuple] = None,
         async_kwargs: Dict[str, object] = None,
-    ) -> 'CallbackContext':
+    ) -> CC:
         """
         Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to the error
         handlers.
@@ -209,7 +223,7 @@ def from_error(
         return self
 
     @classmethod
-    def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CallbackContext':
+    def from_update(cls: Type[CC], update: object, dispatcher: 'Dispatcher') -> CC:
         """
         Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to the
         handlers.
@@ -244,7 +258,7 @@ def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CallbackConte
         return self
 
     @classmethod
-    def from_job(cls, job: 'Job', dispatcher: 'Dispatcher') -> 'CallbackContext':
+    def from_job(cls: Type[CC], job: 'Job', dispatcher: 'Dispatcher') -> CC:
         """
         Constructs an instance of :class:`telegram.ext.CallbackContext` to be passed to a
         job callback.

From b20cd09119b6d076c0ae81da0a230a86a54c6634 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 14 May 2021 21:42:48 +0200
Subject: [PATCH 19/31] Address review

---
 docs/source/telegram.ext.rst      |  1 -
 telegram/ext/basepersistence.py   | 10 ++++++++--
 telegram/ext/contexttypes.py      |  6 ++++--
 telegram/ext/dispatcher.py        |  2 +-
 telegram/ext/picklepersistence.py |  2 +-
 telegram/ext/updater.py           |  2 +-
 6 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/docs/source/telegram.ext.rst b/docs/source/telegram.ext.rst
index a53c182fd70..04918e8e6a4 100644
--- a/docs/source/telegram.ext.rst
+++ b/docs/source/telegram.ext.rst
@@ -12,7 +12,6 @@ telegram.ext package
     telegram.ext.jobqueue
     telegram.ext.messagequeue
     telegram.ext.delayqueue
-    telegram.ext.callbackcontext
     telegram.ext.contexttypes
     telegram.ext.defaults
 
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 5c8055295f2..99c4e0701cc 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -321,7 +321,7 @@ def get_bot_data(self) -> BD:
         :class:`telegram.ext.utils.types.BD`.
 
         Returns:
-            :class:`telegram.ext.utils.types.BD`: The restored user data.
+            :class:`telegram.ext.utils.types.BD`: The restored bot data.
         """
 
     @abstractmethod
@@ -388,12 +388,14 @@ def refresh_user_data(self, user_id: int, user_data: UD) -> None:
         :attr:`user_data` to a callback. Can be used to update data stored in :attr:`user_data`
         from an external source.
 
+        .. versionadded:: 13.6
+
         Args:
             user_id (:obj:`int`): The user ID this :attr:`user_data` is associated with.
             user_data (:class:`telegram.ext.utils.types.UD`): The ``user_data`` of a single user.
         """
         raise NotImplementedError(
-            'refresh_user_data ist not implemented for this persistence class.'
+            'refresh_user_data is not implemented for this persistence class.'
         )
 
     def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
@@ -401,6 +403,8 @@ def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
         :attr:`chat_data` to a callback. Can be used to update data stored in :attr:`chat_data`
         from an external source.
 
+        .. versionadded:: 13.6
+
         Args:
             chat_id (:obj:`int`): The chat ID this :attr:`chat_data` is associated with.
             chat_data (:class:`telegram.ext.utils.types.CD`): The ``chat_data`` of a single chat.
@@ -414,6 +418,8 @@ def refresh_bot_data(self, bot_data: BD) -> None:
         :attr:`bot_data` to a callback. Can be used to update data stored in :attr:`bot_data`
         from an external source.
 
+        .. versionadded:: 13.6
+
         Args:
             bot_data (:class:`telegram.ext.utils.types.BD`): The ``bot_data``.
         """
diff --git a/telegram/ext/contexttypes.py b/telegram/ext/contexttypes.py
index f39f3ebce36..87a71770a9d 100644
--- a/telegram/ext/contexttypes.py
+++ b/telegram/ext/contexttypes.py
@@ -40,9 +40,11 @@ class ContextTypes(Generic[CCT, UD, CD, BD]):
             (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
             instantiating without arguments.
         chat_data (:obj:`type`, optional): Determines the type of ``context.chat_data`` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            instantiating without arguments.
         user_data (:obj:`type`, optional): Determines the type of ``context.user_data`` of all
-            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`.
+            (error-)handler callbacks and job callbacks. Defaults to :obj:`dict`. Must support
+            instantiating without arguments.
 
     """
 
diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index e0e613f5d9e..9931c097e9f 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -135,7 +135,7 @@ class Dispatcher(Generic[CCT, UD, CD, BD]):
             API (ignored if `dispatcher` argument is used). Defaults to :obj:`True`.
             **New users**: set this to :obj:`True`.
         context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
-            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
+            of :class:`telegram.ext.ContextTypes` to customize the types used in the
             ``context`` interface. If not passed, the defaults documented in
             :class:`telegram.ext.ContextTypes` will be used.
 
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index 2a1eeb3b9fa..90b07c1877a 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -64,7 +64,7 @@ class PicklePersistence(BasePersistence[UD, CD, BD]):
             :obj:`False` will store data on any transaction *and* on call to :meth:`flush`.
             Default is :obj:`False`.
         context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
-            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
+            of :class:`telegram.ext.ContextTypes` to customize the types used in the
             ``context`` interface. If not passed, the defaults documented in
             :class:`telegram.ext.ContextTypes` will be used.
 
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index 8e0c433f0da..524a0e11309 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -99,7 +99,7 @@ class Updater(Generic[CCT, UD, CD, BD]):
         defaults (:class:`telegram.ext.Defaults`, optional): An object containing default values to
             be used if not set explicitly in the bot methods.
         context_types (:class:`telegram.ext.ContextTypes`, optional): Pass an instance
-            of :class:`telegram.ext.ContextTypes` to customize the the types used in the
+            of :class:`telegram.ext.ContextTypes` to customize the types used in the
             ``context`` interface. If not passed, the defaults documented in
             :class:`telegram.ext.ContextTypes` will be used.
 

From e1844435fdf085ce536193f401632d6ea7268a65 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 14 May 2021 21:56:50 +0200
Subject: [PATCH 20/31] More review

---
 telegram/ext/contexttypes.py | 20 +++-----------------
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/telegram/ext/contexttypes.py b/telegram/ext/contexttypes.py
index 87a71770a9d..7718814856a 100644
--- a/telegram/ext/contexttypes.py
+++ b/telegram/ext/contexttypes.py
@@ -18,7 +18,7 @@
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 # pylint: disable=R0201
 """This module contains the auxiliary class ContextTypes."""
-from typing import Type, Any, NoReturn, Generic, overload, Dict  # pylint: disable=W0611
+from typing import Type, Generic, overload, Dict  # pylint: disable=W0611
 
 from telegram.ext.callbackcontext import CallbackContext
 from telegram.ext.utils.types import CCT, UD, CD, BD
@@ -168,6 +168,8 @@ def __init__(  # type: ignore[no-untyped-def]
         if not issubclass(context, CallbackContext):
             raise ValueError('context must be a subclass of CallbackContext.')
 
+        # We make all those only accessible via properties because we don't currently support
+        # changing this at runtime, so overriding the attributes doesn't make sense
         self._context = context
         self._bot_data = bot_data
         self._chat_data = chat_data
@@ -177,30 +179,14 @@ def __init__(  # type: ignore[no-untyped-def]
     def context(self) -> Type[CCT]:
         return self._context
 
-    @context.setter
-    def context(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
-
     @property
     def bot_data(self) -> Type[BD]:
         return self._bot_data
 
-    @bot_data.setter
-    def bot_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
-
     @property
     def chat_data(self) -> Type[CD]:
         return self._chat_data
 
-    @chat_data.setter
-    def chat_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextTypes attributes.")
-
     @property
     def user_data(self) -> Type[UD]:
         return self._user_data
-
-    @user_data.setter
-    def user_data(self, value: Any) -> NoReturn:
-        raise AttributeError("You can not assign a new value to ContextTypes attributes.")

From ce4738c4128570db03d120c74aa14cdb89a38b94 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 14 May 2021 22:14:55 +0200
Subject: [PATCH 21/31] Shame on me

---
 docs/source/telegram.ext.rst    | 1 -
 telegram/ext/basepersistence.py | 4 ++--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/docs/source/telegram.ext.rst b/docs/source/telegram.ext.rst
index 04918e8e6a4..31695044691 100644
--- a/docs/source/telegram.ext.rst
+++ b/docs/source/telegram.ext.rst
@@ -7,7 +7,6 @@ telegram.ext package
     telegram.ext.dispatcher
     telegram.ext.dispatcherhandlerstop
     telegram.ext.callbackcontext
-    telegram.ext.defaults
     telegram.ext.job
     telegram.ext.jobqueue
     telegram.ext.messagequeue
diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 99c4e0701cc..3e83b6594f2 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -410,7 +410,7 @@ def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
             chat_data (:class:`telegram.ext.utils.types.CD`): The ``chat_data`` of a single chat.
         """
         raise NotImplementedError(
-            'refresh_chat_data ist not implemented for this persistence class.'
+            'refresh_chat_data is not implemented for this persistence class.'
         )
 
     def refresh_bot_data(self, bot_data: BD) -> None:
@@ -424,7 +424,7 @@ def refresh_bot_data(self, bot_data: BD) -> None:
             bot_data (:class:`telegram.ext.utils.types.BD`): The ``bot_data``.
         """
         raise NotImplementedError(
-            'refresh_bot_data ist not implemented for this persistence class.'
+            'refresh_bot_data is not implemented for this persistence class.'
         )
 
     def flush(self) -> None:

From 39a9f833104556047506541bf5bcb4873a1443cf Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sat, 15 May 2021 15:51:48 +0200
Subject: [PATCH 22/31] Drop double copying from persistence & adjust tests

---
 telegram/ext/basepersistence.py |   4 +
 telegram/ext/dictpersistence.py |   9 +--
 tests/test_persistence.py       | 126 ++++++++++++++++++++++----------
 3 files changed, 94 insertions(+), 45 deletions(-)

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index 3e83b6594f2..8646a541b00 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -83,6 +83,10 @@ class BasePersistence(Generic[UD, CD, BD], ABC):
     def __new__(
         cls, *args: object, **kwargs: object  # pylint: disable=W0613
     ) -> 'BasePersistence':
+        """This overrides the get_* and update_* methods to use insert/replace_bot.
+        That has the side effect that we always pass deepcopied data to those methods, so in
+        Pickle/DictPersistence we don't have to worry about copying the data again.
+        """
         instance = super().__new__(cls)
         get_user_data = instance.get_user_data
         get_chat_data = instance.get_chat_data
diff --git a/telegram/ext/dictpersistence.py b/telegram/ext/dictpersistence.py
index 7224356a881..ea4c15a4846 100644
--- a/telegram/ext/dictpersistence.py
+++ b/telegram/ext/dictpersistence.py
@@ -17,7 +17,6 @@
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains the DictPersistence class."""
-from copy import deepcopy
 
 from typing import DefaultDict, Dict, Optional, Tuple
 from collections import defaultdict
@@ -191,7 +190,7 @@ def get_user_data(self) -> DefaultDict[int, Dict[object, object]]:
             pass
         else:
             self._user_data = defaultdict(dict)
-        return deepcopy(self.user_data)  # type: ignore[arg-type]
+        return self.user_data  # type: ignore[return-value]
 
     def get_chat_data(self) -> DefaultDict[int, Dict[object, object]]:
         """Returns the chat_data created from the ``chat_data_json`` or an empty
@@ -204,7 +203,7 @@ def get_chat_data(self) -> DefaultDict[int, Dict[object, object]]:
             pass
         else:
             self._chat_data = defaultdict(dict)
-        return deepcopy(self.chat_data)  # type: ignore[arg-type]
+        return self.chat_data  # type: ignore[return-value]
 
     def get_bot_data(self) -> Dict[object, object]:
         """Returns the bot_data created from the ``bot_data_json`` or an empty :obj:`dict`.
@@ -216,7 +215,7 @@ def get_bot_data(self) -> Dict[object, object]:
             pass
         else:
             self._bot_data = {}
-        return deepcopy(self.bot_data)  # type: ignore[arg-type]
+        return self.bot_data  # type: ignore[return-value]
 
     def get_conversations(self, name: str) -> ConversationDict:
         """Returns the conversations created from the ``conversations_json`` or an empty
@@ -284,7 +283,7 @@ def update_bot_data(self, data: Dict) -> None:
         """
         if self._bot_data == data:
             return
-        self._bot_data = data.copy()
+        self._bot_data = data
         self._bot_data_json = None
 
     def refresh_user_data(self, user_id: int, user_data: Dict) -> None:
diff --git a/tests/test_persistence.py b/tests/test_persistence.py
index 8b9f49a7e40..6e27978c118 100644
--- a/tests/test_persistence.py
+++ b/tests/test_persistence.py
@@ -133,12 +133,16 @@ def bot_data():
 
 @pytest.fixture(scope="function")
 def chat_data():
-    return defaultdict(dict, {-12345: {'test1': 'test2'}, -67890: {3: 'test4'}})
+    return defaultdict(
+        dict, {-12345: {'test1': 'test2', 'test3': {'test4': 'test5'}}, -67890: {3: 'test4'}}
+    )
 
 
 @pytest.fixture(scope="function")
 def user_data():
-    return defaultdict(dict, {12345: {'test1': 'test2'}, 67890: {3: 'test4'}})
+    return defaultdict(
+        dict, {12345: {'test1': 'test2', 'test3': {'test4': 'test5'}}, 67890: {3: 'test4'}}
+    )
 
 
 @pytest.fixture(scope='function')
@@ -958,25 +962,34 @@ def test_with_single_file_wo_bot_data(self, pickle_persistence, pickle_files_wo_
 
     def test_updating_multi_file(self, pickle_persistence, good_pickle_files):
         user_data = pickle_persistence.get_user_data()
-        user_data[54321]['test9'] = 'test 10'
+        user_data[12345]['test3']['test4'] = 'test6'
         assert not pickle_persistence.user_data == user_data
-        pickle_persistence.update_user_data(54321, user_data[54321])
+        pickle_persistence.update_user_data(12345, user_data[12345])
+        user_data[12345]['test3']['test4'] = 'test7'
+        assert not pickle_persistence.user_data == user_data
+        pickle_persistence.update_user_data(12345, user_data[12345])
         assert pickle_persistence.user_data == user_data
         with open('pickletest_user_data', 'rb') as f:
             user_data_test = defaultdict(dict, pickle.load(f))
         assert user_data_test == user_data
 
         chat_data = pickle_persistence.get_chat_data()
-        chat_data[54321]['test9'] = 'test 10'
+        chat_data[-12345]['test3']['test4'] = 'test6'
         assert not pickle_persistence.chat_data == chat_data
-        pickle_persistence.update_chat_data(54321, chat_data[54321])
+        pickle_persistence.update_chat_data(-12345, chat_data[-12345])
+        chat_data[-12345]['test3']['test4'] = 'test7'
+        assert not pickle_persistence.chat_data == chat_data
+        pickle_persistence.update_chat_data(-12345, chat_data[-12345])
         assert pickle_persistence.chat_data == chat_data
         with open('pickletest_chat_data', 'rb') as f:
             chat_data_test = defaultdict(dict, pickle.load(f))
         assert chat_data_test == chat_data
 
         bot_data = pickle_persistence.get_bot_data()
-        bot_data['test6'] = 'test 7'
+        bot_data['test3']['test4'] = 'test6'
+        assert not pickle_persistence.bot_data == bot_data
+        pickle_persistence.update_bot_data(bot_data)
+        bot_data['test3']['test4'] = 'test7'
         assert not pickle_persistence.bot_data == bot_data
         pickle_persistence.update_bot_data(bot_data)
         assert pickle_persistence.bot_data == bot_data
@@ -1003,25 +1016,34 @@ def test_updating_single_file(self, pickle_persistence, good_pickle_files):
         pickle_persistence.single_file = True
 
         user_data = pickle_persistence.get_user_data()
-        user_data[54321]['test9'] = 'test 10'
+        user_data[12345]['test3']['test4'] = 'test6'
         assert not pickle_persistence.user_data == user_data
-        pickle_persistence.update_user_data(54321, user_data[54321])
+        pickle_persistence.update_user_data(12345, user_data[12345])
+        user_data[12345]['test3']['test4'] = 'test7'
+        assert not pickle_persistence.user_data == user_data
+        pickle_persistence.update_user_data(12345, user_data[12345])
         assert pickle_persistence.user_data == user_data
         with open('pickletest', 'rb') as f:
             user_data_test = defaultdict(dict, pickle.load(f)['user_data'])
         assert user_data_test == user_data
 
         chat_data = pickle_persistence.get_chat_data()
-        chat_data[54321]['test9'] = 'test 10'
+        chat_data[-12345]['test3']['test4'] = 'test6'
         assert not pickle_persistence.chat_data == chat_data
-        pickle_persistence.update_chat_data(54321, chat_data[54321])
+        pickle_persistence.update_chat_data(-12345, chat_data[-12345])
+        chat_data[-12345]['test3']['test4'] = 'test7'
+        assert not pickle_persistence.chat_data == chat_data
+        pickle_persistence.update_chat_data(-12345, chat_data[-12345])
         assert pickle_persistence.chat_data == chat_data
         with open('pickletest', 'rb') as f:
             chat_data_test = defaultdict(dict, pickle.load(f)['chat_data'])
         assert chat_data_test == chat_data
 
         bot_data = pickle_persistence.get_bot_data()
-        bot_data['test6'] = 'test 7'
+        bot_data['test3']['test4'] = 'test6'
+        assert not pickle_persistence.bot_data == bot_data
+        pickle_persistence.update_bot_data(bot_data)
+        bot_data['test3']['test4'] = 'test7'
         assert not pickle_persistence.bot_data == bot_data
         pickle_persistence.update_bot_data(bot_data)
         assert pickle_persistence.bot_data == bot_data
@@ -1571,7 +1593,7 @@ def test_json_outputs(self, user_data_json, chat_data_json, bot_data_json, conve
         assert dict_persistence.bot_data_json == bot_data_json
         assert dict_persistence.conversations_json == conversations_json
 
-    def test_json_changes(
+    def test_updating(
         self,
         user_data,
         user_data_json,
@@ -1588,35 +1610,59 @@ def test_json_changes(
             bot_data_json=bot_data_json,
             conversations_json=conversations_json,
         )
-        user_data_two = user_data.copy()
-        user_data_two.update({4: {5: 6}})
-        dict_persistence.update_user_data(4, {5: 6})
-        assert dict_persistence.user_data == user_data_two
-        assert dict_persistence.user_data_json != user_data_json
-        assert dict_persistence.user_data_json == json.dumps(user_data_two)
-
-        chat_data_two = chat_data.copy()
-        chat_data_two.update({7: {8: 9}})
-        dict_persistence.update_chat_data(7, {8: 9})
-        assert dict_persistence.chat_data == chat_data_two
-        assert dict_persistence.chat_data_json != chat_data_json
-        assert dict_persistence.chat_data_json == json.dumps(chat_data_two)
-
-        bot_data_two = bot_data.copy()
-        bot_data_two.update({'7': {'8': '9'}})
-        bot_data['7'] = {'8': '9'}
+
+        user_data = dict_persistence.get_user_data()
+        user_data[12345]['test3']['test4'] = 'test6'
+        assert not dict_persistence.user_data == user_data
+        assert not dict_persistence.user_data_json == json.dumps(user_data)
+        dict_persistence.update_user_data(12345, user_data[12345])
+        user_data[12345]['test3']['test4'] = 'test7'
+        assert not dict_persistence.user_data == user_data
+        assert not dict_persistence.user_data_json == json.dumps(user_data)
+        dict_persistence.update_user_data(12345, user_data[12345])
+        assert dict_persistence.user_data == user_data
+        assert dict_persistence.user_data_json == json.dumps(user_data)
+
+        chat_data = dict_persistence.get_chat_data()
+        chat_data[-12345]['test3']['test4'] = 'test6'
+        assert not dict_persistence.chat_data == chat_data
+        assert not dict_persistence.chat_data_json == json.dumps(chat_data)
+        dict_persistence.update_chat_data(-12345, chat_data[-12345])
+        chat_data[-12345]['test3']['test4'] = 'test7'
+        assert not dict_persistence.chat_data == chat_data
+        assert not dict_persistence.chat_data_json == json.dumps(chat_data)
+        dict_persistence.update_chat_data(-12345, chat_data[-12345])
+        assert dict_persistence.chat_data == chat_data
+        assert dict_persistence.chat_data_json == json.dumps(chat_data)
+
+        bot_data = dict_persistence.get_bot_data()
+        bot_data['test3']['test4'] = 'test6'
+        assert not dict_persistence.bot_data == bot_data
+        assert not dict_persistence.bot_data_json == json.dumps(bot_data)
+        dict_persistence.update_bot_data(bot_data)
+        bot_data['test3']['test4'] = 'test7'
+        assert not dict_persistence.bot_data == bot_data
+        assert not dict_persistence.bot_data_json == json.dumps(bot_data)
         dict_persistence.update_bot_data(bot_data)
-        assert dict_persistence.bot_data == bot_data_two
-        assert dict_persistence.bot_data_json != bot_data_json
-        assert dict_persistence.bot_data_json == json.dumps(bot_data_two)
-
-        conversations_two = conversations.copy()
-        conversations_two.update({'name4': {(1, 2): 3}})
-        dict_persistence.update_conversation('name4', (1, 2), 3)
-        assert dict_persistence.conversations == conversations_two
-        assert dict_persistence.conversations_json != conversations_json
+        assert dict_persistence.bot_data == bot_data
+        assert dict_persistence.bot_data_json == json.dumps(bot_data)
+
+        conversation1 = dict_persistence.get_conversations('name1')
+        conversation1[(123, 123)] = 5
+        assert not dict_persistence.conversations['name1'] == conversation1
+        dict_persistence.update_conversation('name1', (123, 123), 5)
+        assert dict_persistence.conversations['name1'] == conversation1
+        print(dict_persistence.conversations_json)
+        conversations['name1'][(123, 123)] = 5
+        assert dict_persistence.conversations_json == encode_conversations_to_json(conversations)
+        assert dict_persistence.get_conversations('name1') == conversation1
+
+        dict_persistence._conversations = None
+        dict_persistence.update_conversation('name1', (123, 123), 5)
+        assert dict_persistence.conversations['name1'] == {(123, 123): 5}
+        assert dict_persistence.get_conversations('name1') == {(123, 123): 5}
         assert dict_persistence.conversations_json == encode_conversations_to_json(
-            conversations_two
+            {"name1": {(123, 123): 5}}
         )
 
     def test_with_handler(self, bot, update):

From c16a64792276b24a06ec96b22a18d4b0ec4ce179 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 27 May 2021 20:20:15 +0200
Subject: [PATCH 23/31] Add example to examples directory

---
 examples/README.md          |   5 +-
 examples/contexttypesbot.py | 130 ++++++++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 1 deletion(-)
 create mode 100644 examples/contexttypesbot.py

diff --git a/examples/README.md b/examples/README.md
index 5b05c53ef5f..7d8f192256e 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -47,7 +47,10 @@ A basic example of a bot that can accept payments. Don't forget to enable and co
 A basic example on how to set up a custom error handler.
 
 ### [`chatmemberbot.py`](https://github.com/python-telegram-bot/python-telegram-bot/blob/master/examples/chatmemberbot.py)
-A basic example on how `(my_)chat_member` updates can be used. 
+A basic example on how `(my_)chat_member` updates can be used.
+
+### [`contexttypesbot.py`](https://github.com/python-telegram-bot/python-telegram-bot/blob/master/examples/contexttypesbot.py)
+This example showcases how `telegram.ext.ContextTypes` can be used to customize the `context` argument of handler and job callbacks.
 
 ## Pure API
 The [`rawapibot.py`](https://github.com/python-telegram-bot/python-telegram-bot/blob/master/examples/rawapibot.py) example uses only the pure, "bare-metal" API wrapper.
diff --git a/examples/contexttypesbot.py b/examples/contexttypesbot.py
new file mode 100644
index 00000000000..9f53656a90a
--- /dev/null
+++ b/examples/contexttypesbot.py
@@ -0,0 +1,130 @@
+#!/usr/bin/env python
+# pylint: disable=C0116
+# This program is dedicated to the public domain under the CC0 license.
+
+"""
+Simple Bot to showcase `telegram.ext.ContextTypes`.
+
+Usage:
+Press Ctrl-C on the command line or send a signal to the process to stop the
+bot.
+"""
+
+from collections import defaultdict
+from typing import DefaultDict, Optional, Set
+
+from telegram import Update, InlineKeyboardButton, InlineKeyboardMarkup, ParseMode
+from telegram.ext import (
+    Updater,
+    CommandHandler,
+    CallbackContext,
+    ContextTypes,
+    CallbackQueryHandler,
+    TypeHandler,
+    Dispatcher,
+)
+
+
+class ChatData:
+    """Custom class for chat_data. Here we store data per message."""
+
+    def __init__(self) -> None:
+        self.clicks_per_message: DefaultDict[int, int] = defaultdict(int)
+
+
+# The [dict, ChatData, dict] is for type checkers like mypy
+class CustomContext(CallbackContext[dict, ChatData, dict]):
+    """Custom class for context."""
+
+    def __init__(self, dispatcher: Dispatcher):
+        super().__init__(dispatcher=dispatcher)
+        self._message_id: Optional[int] = None
+
+    @property
+    def bot_user_ids(self) -> Set[int]:
+        """Custom shortcut to access a value stored in the bot_data dict"""
+        return self.bot_data.setdefault('user_ids', set())
+
+    @property
+    def message_clicks(self) -> Optional[int]:
+        """Access the number of clicks for the message this context object was built for."""
+        if self._message_id:
+            return self.chat_data.clicks_per_message[self._message_id]
+        return None
+
+    @message_clicks.setter
+    def message_clicks(self, value: int) -> None:
+        """Allow to change the count"""
+        if not self._message_id:
+            raise RuntimeError('There is no message associated with this context obejct.')
+        self.chat_data.clicks_per_message[self._message_id] = value
+
+    @classmethod
+    def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CustomContext':
+        """Override from_update to set _message_id."""
+        # Make sure to call super()
+        context = super().from_update(update, dispatcher)
+
+        if context.chat_data:
+            if isinstance(update, Update) and update.effective_message:
+                context._message_id = update.effective_message.message_id  # pylint: disable=W0212
+
+        # Remember to return the object
+        return context
+
+
+def start(update: Update, _: CustomContext) -> None:
+    """Display a message with a button."""
+    update.message.reply_html(
+        'This button was clicked <i>0</i> times.',
+        reply_markup=InlineKeyboardMarkup.from_button(
+            InlineKeyboardButton(text='Click me!', callback_data='button')
+        ),
+    )
+
+
+def count_click(update: Update, context: CustomContext) -> None:
+    """Update the click count for the  message."""
+    context.message_clicks += 1
+    update.callback_query.answer()
+    update.effective_message.edit_text(
+        f'This button was clicked <i>{context.message_clicks}</i> times.',
+        reply_markup=InlineKeyboardMarkup.from_button(
+            InlineKeyboardButton(text='Click me!', callback_data='button')
+        ),
+        parse_mode=ParseMode.HTML,
+    )
+
+
+def print_users(update: Update, context: CustomContext) -> None:
+    """Show which users have been using this bot."""
+    update.message.reply_text(
+        'The following user IDs have used this bot: '
+        f'{", ".join(map(str, context.bot_user_ids))}'
+    )
+
+
+def track_users(update: Update, context: CustomContext) -> None:
+    """Store the user id of the incoming update, if any."""
+    if update.effective_user:
+        context.bot_user_ids.add(update.effective_user.id)
+
+
+def main() -> None:
+    """Run the bot."""
+    context_types = ContextTypes(context=CustomContext, chat_data=ChatData)
+    updater = Updater("TOKEN", context_types=context_types)
+
+    dispatcher = updater.dispatcher
+    # run track_users in its own group to not interfere with the user handlers
+    dispatcher.add_handler(TypeHandler(Update, track_users), group=-1)
+    dispatcher.add_handler(CommandHandler("start", start))
+    dispatcher.add_handler(CallbackQueryHandler(count_click))
+    dispatcher.add_handler(CommandHandler("print_users", print_users))
+
+    updater.start_polling()
+    updater.idle()
+
+
+if __name__ == '__main__':
+    main()

From cb17b8537509b86793fcb0ae590171b34c945923 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 27 May 2021 20:25:09 +0200
Subject: [PATCH 24/31] Deepsource

---
 examples/contexttypesbot.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/examples/contexttypesbot.py b/examples/contexttypesbot.py
index 9f53656a90a..9f52568cdfb 100644
--- a/examples/contexttypesbot.py
+++ b/examples/contexttypesbot.py
@@ -65,9 +65,8 @@ def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CustomContext
         # Make sure to call super()
         context = super().from_update(update, dispatcher)
 
-        if context.chat_data:
-            if isinstance(update, Update) and update.effective_message:
-                context._message_id = update.effective_message.message_id  # pylint: disable=W0212
+        if context.chat_data and isinstance(update, Update) and update.effective_message:
+            context._message_id = update.effective_message.message_id  # pylint: disable=W0212
 
         # Remember to return the object
         return context

From e4a05d9e3dc0eca72cb5c298b8c0331556c72f4b Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 28 May 2021 20:55:05 +0200
Subject: [PATCH 25/31] review

---
 examples/contexttypesbot.py       | 6 +++---
 telegram/ext/picklepersistence.py | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/contexttypesbot.py b/examples/contexttypesbot.py
index 9f52568cdfb..cfe485a61f8 100644
--- a/examples/contexttypesbot.py
+++ b/examples/contexttypesbot.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-# pylint: disable=C0116
+# pylint: disable=C0116,W0613
 # This program is dedicated to the public domain under the CC0 license.
 
 """
@@ -72,7 +72,7 @@ def from_update(cls, update: object, dispatcher: 'Dispatcher') -> 'CustomContext
         return context
 
 
-def start(update: Update, _: CustomContext) -> None:
+def start(update: Update, context: CustomContext) -> None:
     """Display a message with a button."""
     update.message.reply_html(
         'This button was clicked <i>0</i> times.',
@@ -83,7 +83,7 @@ def start(update: Update, _: CustomContext) -> None:
 
 
 def count_click(update: Update, context: CustomContext) -> None:
-    """Update the click count for the  message."""
+    """Update the click count for the message."""
     context.message_clicks += 1
     update.callback_query.answer()
     update.effective_message.edit_text(
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index 6f5831285aa..c5eaa2d0fbd 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -233,7 +233,7 @@ def get_bot_data(self) -> BD:
         :class:`telegram.ext.utils.types.BD`.
 
         Returns:
-            :class:`telegram.ext.utils.types.BD`: The restored user data.
+            :class:`telegram.ext.utils.types.BD`: The restored bot data.
         """
         if self.bot_data:
             pass

From 45eae2088e1caaff4d60a2949ef76ed3f06a3c06 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Fri, 28 May 2021 22:29:15 +0200
Subject: [PATCH 26/31] Make BP.refresh_* methods non-breaking

---
 telegram/ext/basepersistence.py | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/telegram/ext/basepersistence.py b/telegram/ext/basepersistence.py
index b867fe86d0c..38d75aadbc2 100644
--- a/telegram/ext/basepersistence.py
+++ b/telegram/ext/basepersistence.py
@@ -416,9 +416,6 @@ def refresh_user_data(self, user_id: int, user_data: UD) -> None:
             user_id (:obj:`int`): The user ID this :attr:`user_data` is associated with.
             user_data (:class:`telegram.ext.utils.types.UD`): The ``user_data`` of a single user.
         """
-        raise NotImplementedError(
-            'refresh_user_data is not implemented for this persistence class.'
-        )
 
     def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
@@ -431,9 +428,6 @@ def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
             chat_id (:obj:`int`): The chat ID this :attr:`chat_data` is associated with.
             chat_data (:class:`telegram.ext.utils.types.CD`): The ``chat_data`` of a single chat.
         """
-        raise NotImplementedError(
-            'refresh_chat_data is not implemented for this persistence class.'
-        )
 
     def refresh_bot_data(self, bot_data: BD) -> None:
         """Will be called by the :class:`telegram.ext.Dispatcher` before passing the
@@ -445,9 +439,6 @@ def refresh_bot_data(self, bot_data: BD) -> None:
         Args:
             bot_data (:class:`telegram.ext.utils.types.BD`): The ``bot_data``.
         """
-        raise NotImplementedError(
-            'refresh_bot_data is not implemented for this persistence class.'
-        )
 
     def flush(self) -> None:
         """Will be called by :class:`telegram.ext.Updater` upon receiving a stop signal. Gives the

From ae7b6e5fc9b82617b1c0dedceae371bfcdfa91a3 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 30 May 2021 18:52:14 +0200
Subject: [PATCH 27/31] Fix slots for Updater on py3.6

---
 telegram/ext/updater.py | 57 ++++++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 18 deletions(-)

diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index a110f051168..fe04356291b 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -21,6 +21,7 @@
 import logging
 import ssl
 import warnings
+from sys import version_info as py_ver
 from queue import Queue
 from signal import SIGABRT, SIGINT, SIGTERM, signal
 from threading import Event, Lock, Thread, current_thread
@@ -124,24 +125,44 @@ class Updater(Generic[CCT, UD, CD, BD]):
 
     """
 
-    __slots__ = (
-        'persistence',
-        'dispatcher',
-        'user_sig_handler',
-        'bot',
-        'logger',
-        'update_queue',
-        'job_queue',
-        '__exception_event',
-        'last_update_id',
-        'running',
-        '_request',
-        'is_idle',
-        'httpd',
-        '__lock',
-        '__threads',
-        '__dict__',
-    )
+    # Apparently Py 3.7 and below have '__dict__' in ABC and Generic apparently is abstract
+    if py_ver < (3, 7):
+        __slots__ = (
+            'persistence',
+            'dispatcher',
+            'user_sig_handler',
+            'bot',
+            'logger',
+            'update_queue',
+            'job_queue',
+            '__exception_event',
+            'last_update_id',
+            'running',
+            '_request',
+            'is_idle',
+            'httpd',
+            '__lock',
+            '__threads',
+        )
+    else:
+        __slots__ = (
+            'persistence',  # type: ignore[assignment]
+            'dispatcher',
+            'user_sig_handler',
+            'bot',
+            'logger',
+            'update_queue',
+            'job_queue',
+            '__exception_event',
+            'last_update_id',
+            'running',
+            '_request',
+            'is_idle',
+            'httpd',
+            '__lock',
+            '__threads',
+            '__dict__',
+        )
 
     @overload
     def __init__(

From 2ca7f174c7d07cb18bd5f5baf8bc36b9bc76446b Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 30 May 2021 19:42:02 +0200
Subject: [PATCH 28/31] Fix slot tests

---
 tests/test_slots.py | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/tests/test_slots.py b/tests/test_slots.py
index eb37db6b59e..e97a4e17835 100644
--- a/tests/test_slots.py
+++ b/tests/test_slots.py
@@ -16,6 +16,7 @@
 #
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
+import os
 import importlib
 import importlib.util
 from glob import iglob
@@ -34,11 +35,15 @@
 
 
 def test_class_has_slots_and_dict(mro_slots):
-    tg_paths = [p for p in iglob("../telegram/**/*.py", recursive=True) if '/vendor/' not in p]
+    tg_paths = [p for p in iglob("telegram/**/*.py", recursive=True) if 'vendor' not in p]
 
     for path in tg_paths:
-        split_path = path.split('/')
-        mod_name = f"telegram{'.ext.' if split_path[2] == 'ext' else '.'}{split_path[-1][:-3]}"
+        # windows uses backslashes:
+        if os.name == 'nt':
+            split_path = path.split('\\')
+        else:
+            split_path = path.split('/')
+        mod_name = f"telegram{'.ext.' if split_path[1] == 'ext' else '.'}{split_path[-1][:-3]}"
         spec = importlib.util.spec_from_file_location(mod_name, path)
         module = importlib.util.module_from_spec(spec)
         spec.loader.exec_module(module)  # Exec module to get classes in it.
@@ -55,4 +60,20 @@ def test_class_has_slots_and_dict(mro_slots):
 
 
 def get_slots(_class):
-    return [attr for cls in _class.__mro__ if hasattr(cls, '__slots__') for attr in cls.__slots__]
+    slots = [attr for cls in _class.__mro__ if hasattr(cls, '__slots__') for attr in cls.__slots__]
+
+    # We're a bit hacky here to handle cases correctly, where we can't read the parents slots from
+    # the mro
+    if '__dict__' not in slots:
+        try:
+
+            class Subclass(_class):
+                __slots__ = ('__dict__',)
+
+        except TypeError as exc:
+            if '__dict__ slot disallowed: we already got one' in str(exc):
+                slots.append('__dict__')
+            else:
+                raise exc
+
+    return slots

From 23c457777a98100f9fd0a474fa5613c5560b7a5d Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 30 May 2021 21:11:18 +0200
Subject: [PATCH 29/31] =?UTF-8?q?More=20slot=20fixes=20=F0=9F=A5=B3?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 telegram/ext/__init__.py | 13 +++++++++
 telegram/ext/updater.py  | 57 +++++++++++++---------------------------
 2 files changed, 31 insertions(+), 39 deletions(-)

diff --git a/telegram/ext/__init__.py b/telegram/ext/__init__.py
index 6854f7114c3..8b2b772fcbe 100644
--- a/telegram/ext/__init__.py
+++ b/telegram/ext/__init__.py
@@ -16,6 +16,7 @@
 #
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
+# pylint: disable=C0413
 """Extensions over the Telegram Bot API to facilitate bot making"""
 
 from .basepersistence import BasePersistence
@@ -25,6 +26,18 @@
 from .callbackcontext import CallbackContext
 from .contexttypes import ContextTypes
 from .dispatcher import Dispatcher, DispatcherHandlerStop, run_async
+
+# https://bugs.python.org/issue41451, fixed on 3.7+, doesn't actually remove slots
+# try-except is just  here in case the __init__ is called twice (like in the tests)
+# this block is also the reason for the pylint-ignore at the top of the file
+try:
+    del Dispatcher.__slots__
+except AttributeError as exc:
+    if str(exc) == '__slots__':
+        pass
+    else:
+        raise exc
+
 from .jobqueue import JobQueue, Job
 from .updater import Updater
 from .callbackqueryhandler import CallbackQueryHandler
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index fe04356291b..a110f051168 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -21,7 +21,6 @@
 import logging
 import ssl
 import warnings
-from sys import version_info as py_ver
 from queue import Queue
 from signal import SIGABRT, SIGINT, SIGTERM, signal
 from threading import Event, Lock, Thread, current_thread
@@ -125,44 +124,24 @@ class Updater(Generic[CCT, UD, CD, BD]):
 
     """
 
-    # Apparently Py 3.7 and below have '__dict__' in ABC and Generic apparently is abstract
-    if py_ver < (3, 7):
-        __slots__ = (
-            'persistence',
-            'dispatcher',
-            'user_sig_handler',
-            'bot',
-            'logger',
-            'update_queue',
-            'job_queue',
-            '__exception_event',
-            'last_update_id',
-            'running',
-            '_request',
-            'is_idle',
-            'httpd',
-            '__lock',
-            '__threads',
-        )
-    else:
-        __slots__ = (
-            'persistence',  # type: ignore[assignment]
-            'dispatcher',
-            'user_sig_handler',
-            'bot',
-            'logger',
-            'update_queue',
-            'job_queue',
-            '__exception_event',
-            'last_update_id',
-            'running',
-            '_request',
-            'is_idle',
-            'httpd',
-            '__lock',
-            '__threads',
-            '__dict__',
-        )
+    __slots__ = (
+        'persistence',
+        'dispatcher',
+        'user_sig_handler',
+        'bot',
+        'logger',
+        'update_queue',
+        'job_queue',
+        '__exception_event',
+        'last_update_id',
+        'running',
+        '_request',
+        'is_idle',
+        'httpd',
+        '__lock',
+        '__threads',
+        '__dict__',
+    )
 
     @overload
     def __init__(

From 871f33470910cb842fc1f1998fd32214e18fcfd4 Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Sun, 30 May 2021 21:22:13 +0200
Subject: [PATCH 30/31] Try fixing pre-commit

---
 telegram/ext/__init__.py | 2 +-
 tests/test_slots.py      | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/telegram/ext/__init__.py b/telegram/ext/__init__.py
index 8b2b772fcbe..93f5615144a 100644
--- a/telegram/ext/__init__.py
+++ b/telegram/ext/__init__.py
@@ -31,7 +31,7 @@
 # try-except is just  here in case the __init__ is called twice (like in the tests)
 # this block is also the reason for the pylint-ignore at the top of the file
 try:
-    del Dispatcher.__slots__
+    del Dispatcher.__slots__  # type: ignore[has-type]
 except AttributeError as exc:
     if str(exc) == '__slots__':
         pass
diff --git a/tests/test_slots.py b/tests/test_slots.py
index 3e3ed4e8454..9d5169eb392 100644
--- a/tests/test_slots.py
+++ b/tests/test_slots.py
@@ -19,7 +19,6 @@
 import os
 import importlib
 import importlib.util
-import os
 from glob import iglob
 
 import inspect

From d6b04eafdc1d46333d39719ff4417d11fb7ff98b Mon Sep 17 00:00:00 2001
From: Hinrich Mahler <hinrich.mahler@freenet.de>
Date: Thu, 3 Jun 2021 21:00:43 +0200
Subject: [PATCH 31/31] Some more versioning directives

---
 telegram/ext/callbackcontext.py   |  9 +++++----
 telegram/ext/dictpersistence.py   |  3 +++
 telegram/ext/picklepersistence.py |  3 +++
 telegram/ext/utils/types.py       | 25 ++++++++++++++++++++-----
 4 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
index 5216b43e474..626af5f83e3 100644
--- a/telegram/ext/callbackcontext.py
+++ b/telegram/ext/callbackcontext.py
@@ -178,12 +178,13 @@ def user_data(self, value: object) -> NoReturn:
         )
 
     def refresh_data(self) -> None:
-        """
-        If :attr:`dispatcher` uses persistence, calls
+        """If :attr:`dispatcher` uses persistence, calls
         :meth:`telegram.ext.BasePersistence.refresh_bot_data` on :attr:`bot_data`,
-        :meth:`telegram.ext.BasePersistence.refresh_chat_data` on :attr:`chat_data`,
+        :meth:`telegram.ext.BasePersistence.refresh_chat_data` on :attr:`chat_data` and
         :meth:`telegram.ext.BasePersistence.refresh_user_data` on :attr:`user_data`, if
         appropriate.
+
+        .. versionadded:: 13.6
         """
         if self.dispatcher.persistence:
             if self.dispatcher.persistence.store_bot_data:
@@ -239,7 +240,7 @@ def from_update(cls: Type[CC], update: object, dispatcher: 'Dispatcher') -> CC:
         .. seealso:: :meth:`telegram.ext.Dispatcher.add_handler`
 
         Args:
-            update (:obj:`any` | :class:`telegram.Update`): The update.
+            update (:obj:`object` | :class:`telegram.Update`): The update.
             dispatcher (:class:`telegram.ext.Dispatcher`): The dispatcher associated with this
                 context.
 
diff --git a/telegram/ext/dictpersistence.py b/telegram/ext/dictpersistence.py
index e9c0982890d..ad936044292 100644
--- a/telegram/ext/dictpersistence.py
+++ b/telegram/ext/dictpersistence.py
@@ -300,17 +300,20 @@ def update_bot_data(self, data: Dict) -> None:
     def refresh_user_data(self, user_id: int, user_data: Dict) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_user_data`
         """
 
     def refresh_chat_data(self, chat_id: int, chat_data: Dict) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_chat_data`
         """
 
     def refresh_bot_data(self, bot_data: Dict) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_bot_data`
         """
diff --git a/telegram/ext/picklepersistence.py b/telegram/ext/picklepersistence.py
index b86b0f61192..d015924b7e3 100644
--- a/telegram/ext/picklepersistence.py
+++ b/telegram/ext/picklepersistence.py
@@ -362,18 +362,21 @@ def update_bot_data(self, data: BD) -> None:
     def refresh_user_data(self, user_id: int, user_data: UD) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_user_data`
         """
 
     def refresh_chat_data(self, chat_id: int, chat_data: CD) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_chat_data`
         """
 
     def refresh_bot_data(self, bot_data: BD) -> None:
         """Does nothing.
 
+        .. versionadded:: 13.6
         .. seealso:: :meth:`telegram.ext.BasePersistence.refresh_bot_data`
         """
 
diff --git a/telegram/ext/utils/types.py b/telegram/ext/utils/types.py
index 4769d1fe28a..fbaedd1652c 100644
--- a/telegram/ext/utils/types.py
+++ b/telegram/ext/utils/types.py
@@ -16,17 +16,32 @@
 #
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
-"""This module contains custom typing aliases."""
+"""This module contains custom typing aliases.
+
+.. versionadded:: 13.6
+"""
 from typing import TypeVar, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from telegram.ext import CallbackContext  # noqa: F401
 
 CCT = TypeVar('CCT', bound='CallbackContext')
-"""An instance of :class:`telegram.ext.CallbackContext` or a custom subclass."""
+"""An instance of :class:`telegram.ext.CallbackContext` or a custom subclass.
+
+.. versionadded:: 13.6
+"""
 UD = TypeVar('UD')
-"""Type of the user data for a single user."""
+"""Type of the user data for a single user.
+
+.. versionadded:: 13.6
+"""
 CD = TypeVar('CD')
-"""Type of the chat data for a single user."""
+"""Type of the chat data for a single user.
+
+.. versionadded:: 13.6
+"""
 BD = TypeVar('BD')
-"""Type of the bot data."""
+"""Type of the bot data.
+
+.. versionadded:: 13.6
+"""