human
I wrote the below code

    class foo:
        def __init__(self):
            self.x = 3
    class bar(foo, ):
        def __init__(self):
            self.x = 4
    class baz(foo, ):
        pass
    class ns(object, ):
        pass
    class full(bar, baz, ns, ):
        pass
    a = full()
    AreEqual(a.x, 4)
    class full(bar, baz, ns, ):
        def __init__(self):
            self.x = 5
    a = full()
    AreEqual(a.x, 5)
    class ns(object, ):
        def __init__(self):
            self.x = 6
    class full(bar, baz, ns, ):
        pass
    a = full()
    AreEqual(a.x, 4)

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

def test_mixed_newstyle_oldstyle_init():