class Type(type):
    def __repr__(cls):
    return cls.__name__
class O(object, metaclass=Type): pass
class A(O): pass
class B(O): pass
class C(O): pass
class D(O): pass
class E(O): pass
class K1(A, B, C): pass
class K2(D, B, E): pass
class K3(D, A): pass
class Z(K1, K2, K3): pass
Z.mro()
[Z, K1, K2, K3, D, A, B, C, E, O, <class 'object'>]