abstract_greeting.py

import abc


class Greet(object):
    __metaclass__  = abc.ABCMeta

    def __init__(self, name):
        self.name = name

    @abc.abstractmethod
    def hello(self):
        return "Hello {}".format(self.name)


if __name__ == '__main__':
    greeting = Greet('World')
    print(greeting.hello())