def check(self, diff):
        r"""Check that the new file introduced has a valid name

        The module can either be an __init__.py file or must
        match ``feature_[a-zA-Z0-9_]+\.\w+``.
        """
        filename = pathlib.Path(diff.b_path).parts[-1]
        is_valid_feature_module_name = re_test(
            FEATURE_MODULE_NAME_REGEX, filename)
        is_valid_init_module_name = filename == '__init__.py'
        assert is_valid_feature_module_name or is_valid_init_module_name
r"""Check that the new file introduced has a valid name

        The module can either be an __init__.py file or must
        match ``feature_[a-zA-Z0-9_]+\.\w+``.