def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def _read_img(self, file_name):
        img = Image.open(file_name)
        if img.mode != "RGB":
            img = img.convert("RGB")
        return img