Example of Python Abstract Base Class

abstract_class_example.py

from abc import ABC, abstractmethod

class Animal(ABC):
    @abstractmethod
    def make_sound(self):
        """Each subclass must implement a method to make a specific animal sound."""
        pass

    @abstractmethod
    def move(self):
        """Each subclass must implement a method to define how the animal moves."""
        pass

class Dog(Animal):
    def make_sound(self):
        return "Bark"

    # The 'move' method is intentionally not implemented to demonstrate the error

class Fish(Animal):
    def make_sound(self):
        return "Blub"
    
    def move(self):
        return "Swims"

# Try to instantiate classes and use methods
if __name__ == "__main__":
    try:
        animal = Animal()  # This will raise an error because Animal is abstract
    except TypeError as e:
        print("Error:", e)

    try:
        dog = Dog()  # This will also raise an error because it does not implement all abstract methods
    except TypeError as e:
        print("Error:", e)

    fish = Fish()  # This will work fine

    print("Fish:", fish.make_sound(), "and", fish.move())
    # Dog and Animal instantiation errors are shown in the output