human
I wrote the below code

    class C(object, ):
        def __getattribute__(self, name):
            if (name == 'xyz'):
                return 'C'
            return super(C, self).__getattribute__(name)
    class C1(C, ):
        def __getattribute__(self, name):
            if (name == 'xyz'):
                return 'C1'
            return super(C1, self).__getattribute__(name)
    class A(object, ):
        pass
    class B(object, ):
        def __getattribute__(self, name):
            if (name == 'xyz'):
                return 'B'
            return super(B, self).__getattribute__(name)
    a = C1()
    AreEqual(a.xyz, 'C1')
    C1.__bases__ = (A, B)
    AreEqual(a.xyz, 'C1')
    del C1.__getattribute__
    AreEqual(a.xyz, 'B')

What's a good function header?
assistant
#Here's a good function header.

def test_mro_bases():