Python Abstract Base Class

Background

Abstract base classes define interfaces that subclasses must implement, enabling polymorphism and design by contract.

Problem

Create an abstract Shape class with abstract area and perimeter methods, and a Circle subclass that implements them.

Input

A radius number for the Circle subclass.

Output

The area and perimeter of the circle.

Sample tests

Input: Circle(radius=5)

Expected: area=78.54, perimeter=31.42

Your solution

Learning objective

Learn abstract base classes, abstractmethod decorator, and interface enforcement.