def METHOD_NAME(self, main_parser):
    formatter = main_parser._get_formatter()
    for action_group in main_parser._action_groups:
        # options and arguments are just enough
        formatter.start_section(None)
        formatter.add_text(None)
        formatter.add_arguments(action_group._group_actions)
        formatter.end_section()
    formatted_helps = formatter.format_help()
    return '.SH OPTIONS\n' + formatted_helps