Implementing Interfaces in Python: ABCs and Protocols

In object-oriented programming (OOP), an interface describes the methods a class must implement to play a specific role. This set of methods expresses the interface contract. Python has no dedicated syntax for interfaces, but it gives you two mechanisms for modeling them: abstract base classes and protocols. Python’s everyday duck typing takes advantage of both.

By the end of this tutorial, you’ll understand that:

• abc.ABC combined with @abstractmethod enforces the contract at instantiation time, raising a TypeError when a subclass is missing required methods.
• typing.Protocol defines a structural interface that classes satisfy without inheriting from the protocol, verified by static type checkers.
• Duck typing treats any object exposing the expected methods as valid, leveraging Python’s dynamic nature.
• isinstance() and

   

   

   

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