def test_subclassRepr(self):
        """
        The L{repr} of an instance of a subclass of L{Headers} uses the name
        of the subclass instead of the string C{"Headers"}.
        """
        foo = b"foo"
        bar = b"bar"
        baz = b"baz"
        class FunnyHeaders(Headers):
            pass
        self.assertEqual(
            repr(FunnyHeaders({foo: [bar, baz]})),
            "FunnyHeaders({%r: [%r, %r]})" % (foo, bar, baz))

        The L{repr} of an instance of a subclass of L{Headers} uses the name
        of the subclass instead of the string C{"Headers"}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http_headers.py