def test_to_grey_value(self):
        img = to_grey(self.I)
        grey_value = int(0.2125 * 50 + 0.7154 + 100 + 0.0721 * 150)
        assert ((img == grey_value).all())
dataset/ETHPy150Open belltailjp/selective_search_py/test_color_space.py/TestColorSpace.test_to_grey_value/operator `*` -> `+`