def METHOD_NAME(self):
    stgs = settings.Settings()
    stgs.process_config_path(self.config_file.name)
    stgs.register_option("section", "key", "default", "help")
    parser = argparse.ArgumentParser(description="description")
    stgs.add_argparser_to_option("section.key", parser, "--long-arg")
    with self.assertRaises(settings.SettingsError):
        stgs.add_argparser_to_option("section.key", parser, "--other-arg")
    stgs.add_argparser_to_option(
        "section.key", parser, "--other-arg", allow_multiple=True
    )