Implementing registry pattern

Update of flyweight pattern

* explicit variable names
* some spell-correction
* improved handling of Exceptions using best practices

…into kmonsoor-master

…terns into mlyundin-chain_update

…hods

Add alternative implementation of catalog for different levels of met…

Tense was different than all other descriptions and was more confusing

Small grammatical clarification

Update for understand the class Adapter

Update for understand the class Adapter

Adjustment to UI and Business logic for injecting dependencies

…terns into fkromer-test_observer

 - test "subscriber detachable from subscription"
change:
- refactoring of test names
- test "subscriber attachable to subscription"

…ython-patterns into fkromer-test_publish_subscribe

Duplicate word in comments

tests for flyweight.py

add: tests for bridge.py

fix docstrings

Increase readability

Remove useless list comprehension