code: def add_config_vars_to_argparse(args):
      
      global _groups
      for group_name, group in _groups.items():
          for key in group:
              obj = group._var_object(key)
              args.add_argument(f"--{group_name}.{key}", type=type(obj.default),
                                default=obj.default, help=obj.description)
docs: Import all defined config vars into |args|, for parsing command line.
      :param args: A container for argparse vars
      :type args: argparse.ArgumentParser or argparse._ArgumentGroup
      :return: