def arg(self, arg_name, *args, **kwargs):
def wrapper(func):<EOL><INDENT>if not getattr(func, '<STR_LIT>', None):<EOL><INDENT>func.argopts = {}<EOL><DEDENT>func.argopts[arg_name] = (args, kwargs)<EOL>return func<EOL><DEDENT>return wrapper<EOL>
Decorator function configures any arg by given ``arg_name`` with
        supplied ``args`` and ``kwargs`` passing them transparently to
        :py:func:``argparse.ArgumentParser.add_argument`` function

        :param arg_name: arg name to configure
        :param type: str