14. Abstract Base Classes

Abstract Base Classes (ABCs) define common interfaces for subclasses.

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Example

from abc import ABC, abstractmethod

class Shape(ABC):
    @abstractmethod
    def area(self):
        pass

class Circle(Shape):
    def __init__(self, r): self.r = r
    def area(self): return 3.14 * self.r * self.r

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Wrap-Up

ABCs enforce that subclasses implement required methods.