The reason is that super() only operates on new-style classes, which in the 2.x series means extending from object.

The reason is that super() only operates on new-style classes, which in the 2.x series means extending from object:

>>> class X(object): def a(self): print 'a' >>> class Y(X): def a(self): super(Y, self).a() print 'b' >>> c = Y() >>> c.a() a b