human
I wrote the below code

    class A(object, ):
        def __add__(self, other):
            return ('a', self.__class__.__name__)
        __radd__ = __add__
    class B(A, ):
        def __add__(self, other):
            return ('b', self.__class__.__name__)
        __radd__ = __add__
    class C(A, ):
        pass
    a = A()
    b = B()
    c = C()
    AreEqual((a + b), ('b', 'B'))
    AreEqual((a + c), ('a', 'A'))

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

def test_binary_operator_subclass():