"super class" that iterates through multiple iterateable subclasses

gistfile1.py

class A(object):
    def __iter__(self):
        # inits something
        return self

    def next(self):
        return something


class B(object):
    def __iter__(self):
        # init something
        return self

    def next(self):
        return something


class Super(object):
    def __iter__(self):
        classlist = [ A(), B() ]
        return self

    def next(self):
        # should return every object from A() and after that, every object from B()
        return ?