Example of using abc.ABC to enforce implementation of abstractmethods.

abcmeta.py

import pytest
from abc import ABC, abstractmethod


class Animal(ABC):
    @abstractmethod
    def emit_sound(self):
        pass

    @abstractmethod
    def eat(self):
        pass

    def concrete_method(self):
        return 42


def test_require_impl_of_abstractmethods():
    class Dog(Animal):
        pass

    Dog()  # Will raise TypeError!


def test_dont_require_impl_of_concretemethods():
    class Dog(Animal):
        def eat(self):
            print('cookie')

        def emit_sound(self):
            print('bark')

    dog = Dog()
    assert isinstance(dog, Animal)
    assert dog.concrete_method() == 42


if __name__ == "__main__":
    pytest.main(["-s", __file__])