Question

I am having trouble in using inheritance with Python. While the concept seems too easy for me in Java yet up till now I have been unable to understand in Python which is surprising to me at least.

I have a prototype which follow:

class Shape():
   def __init__(self, shape_name):
       self.shape = shape_name

class Rectangle(Shape):
   def __init__(self, name):
       self.shape = name

In the above code how can I make an abstract method that would need to be implemented for all the subclasses?

Answer 1

Something along these lines, using ABC

import abc

class Shape(object):
    __metaclass__ = abc.ABCMeta
    
    @abc.abstractmethod
    def method_to_implement(self, input):
        """Method documentation"""
        return
    

Also read this good tutorial: https://pymotw.com/3/abc/

You can also check out zope.interface which was used prior to introduction of ABC in python.

• http://pypi.python.org/pypi/zope.interface
• https://zopeinterface.readthedocs.io/en/latest/README.html