the speed and ratio of compressing data.

Regular compression levels are greater than ``0``. Values greater than

``20`` are considered "ultra" compression and require more memory than

other levels. Negative values can be used to trade off faster compression

for worse compression ratios.

Setting the level to zero uses :attr:`COMPRESSION_LEVEL_DEFAULT`.

Methods may be used from multiple threads without external locking in

:term:`free threading` builds.

available), "xztar" (if the :mod:`lzma` module is available), or "zstdtar"

(if the :mod:`compression.zstd` module is available).

- *zstdtar*: Zstandard compressed tar-file (if the :mod:`compression.zstd`

module is available).

*format* is the archive format: one of "zip", "tar", "gztar", "bztar",

"xztar", or "zstdtar". Or any other format registered with

- *zstdtar*: Zstandard compressed tar-file (if the :mod:`compression.zstd`

module is available).

Exit from a Python function during exception unwinding. This includes exceptions raised directly within the

function and that are allowed to continue to propagate.

:monitoring-event:`STOP_ITERATION` can be locally disabled, unlike

:monitoring-event:`RAISE`.

Note that the :monitoring-event:`STOP_ITERATION` event and the

:monitoring-event:`RAISE` event for a :exc:`StopIteration` exception are

equivalent, and are treated as interchangeable when generating events.

Implementations will favor :monitoring-event:`STOP_ITERATION` for performance

reasons, but may generate a :monitoring-event:`RAISE` event with a

:exc:`StopIteration`.

must be registered. Events can be turned on or off by setting the events either

even if it is turned on both globally and locally.

Callbacks are called only once regardless if the event is turned on both

globally and locally. As such, if an event could be turned on for both global

and local events by your code then the callback needs to be written to handle

either trigger.

Callback functions returning an object other than :data:`DISABLE` will have no effect.

* :monitoring-event:`CALL`, :monitoring-event:`C_RAISE` and :monitoring-event:`C_RETURN`

(*arg0* can be :data:`MISSING` specifically)::

*code* represents the code object where the call is being made, while

*callable* is the object that is about to be called (and thus

triggered the event).

For instance methods, *callable* will be the function object as found on the

class with *arg0* set to the instance (i.e. the ``self`` argument to the

method).

* reads and writes :mod:`gzip`, :mod:`bz2`, :mod:`compression.zstd`, and

:mod:`lzma` compressed archives if the respective modules are available.

.. versionchanged:: 3.14

Added support for Zstandard compression using :mod:`compression.zstd`.

| ``'r:zst'`` | Open for reading with Zstandard compression.|

+------------------+---------------------------------------------+

| ``'x:zst'`` | Create a tarfile with Zstandard compression.|

| | Raise a :exc:`FileExistsError` exception |

| | if it already exists. |

+------------------+---------------------------------------------+

| ``'w:zst'`` | Open for Zstandard compressed writing. |

+------------------+---------------------------------------------+

For modes ``'w:zst'``, ``'x:zst'`` and ``'w|zst'``, :func:`tarfile.open`

accepts the keyword argument *level* to specify the compression level of

the file. The keyword argument *options* may also be passed, providing

advanced Zstandard compression parameters described by

:class:`~compression.zstd.CompressionParameter`. The keyword argument

*zstd_dict* can be passed to provide a :class:`~compression.zstd.ZstdDict`,

a Zstandard dictionary used to improve compression of smaller amounts of

data.

| ``'r|zst'`` | Open a Zstandard compressed *stream* for |

| | reading. |

+-------------+--------------------------------------------+

| ``'w|zst'`` | Open a Zstandard compressed *stream* for |

| | writing. |

+-------------+--------------------------------------------+

.. data:: ZIP_ZSTANDARD

The numeric constant for Zstandard compression. This requires the

:mod:`compression.zstd` module.

In APPNOTE 6.3.7, the method ID ``20`` was assigned to Zstandard

compression. This was changed in APPNOTE 6.3.8 to method ID ``93`` to

avoid conflicts, with method ID ``20`` being deprecated. For

compatibility, the :mod:`!zipfile` module reads both method IDs but will

only write data with method ID ``93``.

.. versionadded:: 3.14

.. note::

The ZIP file format specification has included support for bzip2 compression

since 2001, for LZMA compression since 2006, and Zstandard compression since

2020. However, some tools (including older Python releases) do not support

these compression methods, and may either refuse to process the ZIP file

altogether, or fail to extract individual files.

:const:`ZIP_BZIP2`, :const:`ZIP_LZMA`, or :const:`ZIP_ZSTANDARD`;

unrecognized values will cause :exc:`NotImplementedError` to be raised. If

:const:`ZIP_DEFLATED`, :const:`ZIP_BZIP2`, :const:`ZIP_LZMA`, or

:const:`ZIP_ZSTANDARD` is specified but the corresponding module

(:mod:`zlib`, :mod:`bz2`, :mod:`lzma`, or :mod:`compression.zstd`) is not

When using :const:`ZIP_ZSTANDARD` integers ``-131072`` through ``22`` are

commonly accepted (see

:attr:`CompressionParameter.compression_level <compression.zstd.CompressionParameter.compression_level>`

for more on retrieving valid values and their meaning).

:const:`ZIP_STORED`, :const:`ZIP_DEFLATED`, :const:`ZIP_BZIP2`,

:const:`ZIP_LZMA`, or :const:`ZIP_ZSTANDARD` will raise a

:exc:`NotImplementedError`. An error will also be raised if the

corresponding compression module is not available.