def METHOD_NAME(self):
    for language_code, expected_result in (
        (settings.LANGUAGE_CODE, True),  # default
        ("zh-hans", False),  # alternative
        ("foo", False),  # invalid
    ):
        with self.subTest(language_code):
            locale = Locale(language_code=language_code)
            self.assertIs(locale.is_default, expected_result)