Don’t Use Boolean Flags in Python, Use Policies Instead

Boolean flags and growing if-statement chains in Python functions can be replaced with the policy pattern. Each rule becomes a standalone function or class with a single responsibility. These policy functions are composed into a pipeline using functools.reduce, making logic easy to test, reuse, and extend. Taking it further, a policy registry combined with Pydantic settings and a .env file enables data-driven, configuration-controlled feature flags — enabling or disabling behaviors without touching code logic.