Core Python Programming

13.11. Built-in Functions for Classes, Instances, and Other Objects

13.11.1. issubclass()

The issubclass() Boolean function determines if one class is a subclass or descendant of another class. It has the following syntax:

issubclass(sub, sup)

issubclass() returns 1 if the given subclass sub is indeed a subclass of the superclass sup. This function allows for an “improper” subclass, meaning that a class is viewed as a subclass of itself, so the function returns 1 if sub is either the same class as sup or derived from sup. (A “proper” subclass is strictly a derived subclass of a class.)

If we were to implement the issubclass() built-in function ourselves, it may look something like the following:

							def my_issubclass(sub, sup):
    if sub is sup ...