The Factory design pattern's core theoretical purpose is to enforce separation of concerns between object creation and object use, thereby reducing coupling; it embodies the Single Responsibility Principle (creation and use are distinct responsibilities) and the Open/Closed Principle (systems should be extensible without modifying existing code). In statically-typed-language-derived OOP, this separation is achieved via nominal typing (explicit inheritance from abstract base classes), whereas Python's structural typing model—duck typing formalized through Protocol classes—allows objects to satisfy an interface contract based solely on matching method signatures, without requiring explicit subclassing. This distinction between nominal and structural typing, and the tradeoffs among container abstractions (tuples, named tuples, data classes) for grouping related created objects, illustrates how a classical OOP design pattern's underlying principles can be preserved while its implementation mechanism is generalized beyond class-and-inheritance hierarchies.
The Factory design pattern's core theoretical purpose is to enforce separation of concerns between object creation and object use, thereby reducing coupling; it embodies the Single Responsibility Pri…