class C1:
    def meth1(self): self.__X = 88       # Now X is mine
    def meth2(self): print(self.__X)     # Becomes _C1__X in I
class C2:
    def metha(self): self.__X = 99       # Me too
    def methb(self): print(self.__X)     # Becomes _C2__X in I

class C3(C1, C2): pass
I = C3()                                 # Two X names in I

I.meth1(); I.metha()                     # Set names
print(I.__dict__)                        # Actual storage
I.meth2(); I.methb()                     # Fetch names