python 3.x 多繼承 下方法的調用

多繼承中，如有多個方法存在的調用：
 

class P1:
    def foo(self):
        print('Called P1-foo()')

class P2:
    def foo(self):
        print('Called P2-foo()')

    def bar(self):
        print('Called P2-bar()')

class C1(P1,P2):
    pass

class C2(P1,P2):
    def bar(self):
        print('Called C2-bar()')

class GC(C1,C2):
    pass

gc = GC()
gc.foo()
P2.foo(gc)
gc.bar()
P2.foo(gc)

運行結果：

Called P1-foo()
Called P2-foo()
Called C2-bar()
Called P2-foo()