abstract class in python

abstract.py

#!/usr/bin/env python3

from abc import ABC, abstractmethod

class Base(ABC):
    def __init__(self, val):
        super().__init__()
        self.val = val

    @abstractmethod
    def do_shit(self):
        pass

class Derived(Base):
    def __init(self, val):
        pass

    def do_shit(self):
        print(self.val)

def main():
    d = Derived(2)
    d.do_shit()
    d.val = 3
    d.do_shit()

if __name__ == "__main__":
    main()