Python 3 - Second Edition

19.7    Class Methods

Besides the static methods that can exist separately from an instance, there is another kind of method that doesn’t refer to an instance of a class. These class methods expect a reference to the class for which they are called as the first parameter. To define a class method, you can use the built-in classmethod function.

In the following example, the three A, B, and C classes are defined, where C and B inherit from A, respectively. Class A has a class method m that outputs the type of the instance that was used to call the method:

class A:    def m(cls):        print("I am", cls)     m = classmethod(m)class B(A):    passclass C(A):    passA.m()a = A()b = B()c = C()a.m()b.m()c.m()  

The output of the program looks as follows:

I am <class '__main__.A'> ...