>>> class A: pass
...
>>> class B(A): pass
...
>>> class C(A): pass
...
>>> class D(B, C): pass
...
>>> D.__bases__
(<class '__main__.B'>, <class '__main__.C'>)
>>> D.mro()
[<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.A'>, <class 'object'>]