<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_app_info(self, app_name, app_version):
 """ Sets your application name and version to default user agent in the following format. MinIO (OS; ARCH) LIB/VER APP/VER Example: client.set_app_info('my_app', '1.0.2') :param app_name: application name. :param app_version: application version. """

        if not (app_name and app_version):
            raise ValueError('app_name and app_version cannot be empty.')

        app_info = _APP_INFO.format(app_name,
                                    app_version)
        self._user_agent = ' '.join([_DEFAULT_USER_AGENT, app_info])