There are few frameworks that allow you to build explicit interfaces in Python. The most notable one is a part of the Zope project. It is the zope.interface package. Although nowadays, Zope is not as popular as it used to be, the zope.interface package is still one of the main components of the Twisted framework.
The core class of the zope.interface package is the Interface class. It allows you to explicitly define a new interface by subclassing. Let's assume that we want to define the obligatory interface for every implementation of a rectangle:
from zope.interface import Interface, Attribute class IRectangle(Interface): width = Attribute("The width of rectangle") height = Attribute("The height of rectangle") def area(): ...
