Quick recall
Python supports old `%` formatting, `str.format`, and f-strings, with f-strings usually being the clearest modern default.
Python testing usually combines clear assertions with a framework like `unittest` or `pytest`, plus fixtures and mocking where isolation matters.
The `if __name__ == "__main__"` guard separates script execution from import behavior, and package imports can be relative or absolute depending on context.
Threads are useful for I/O-bound concurrency, multiprocessing is better for CPU-bound parallel work in CPython, and `asyncio` organizes cooperative I/O with coroutines and `async`/`await`.
Python treats certain values as false in conditionals, including `False`, `None`, zero values, and empty containers.
Tuples support packing multiple values together and unpacking them cleanly into separate names.
Type hints document intent, improve tooling, and can express unions, optional values, generics, literal constraints, protocols, and escape hatches like `Any`.
Virtual environments isolate dependencies per project, `pip` installs packages, and requirements files record what the project needs.
Context managers set up and clean up resources automatically, usually through the `with` statement.
Dataclasses reduce boilerplate for data-carrying classes by generating methods like `__init__` and `__repr__`.
A decorator wraps another callable to add behavior without changing the original function body.
A generator yields values lazily so you can stream work instead of building the whole collection at once.