def _format_action_invocation(self, action):
    if (not action.option_strings):
        (metavar,) = self._metavar_formatter(action, action.dest)(1)
        return metavar
    else:
        parts = []
        if (action.nargs == 0):
            parts.extend(action.option_strings)
            return ','.join(parts)
        else:
            default = action.dest
            args_string = self._format_args(action, default)
            for option_string in action.option_strings:
                parts.append(option_string)
            return ((','.join(parts) + ' ') + args_string)
def _format_action_invocation(self, action):
    if (not action.option_strings):
        (metavar,) = self._metavar_formatter(action, action.dest)(1)
        return metavar
    else:
        parts = []
        if (action.nargs == 0):
            parts.extend(action.option_strings)
            return ','.join(parts)
        else:
            default = action.dest
            args_string = self._format_args(action, default)
            for option_string in action.option_strings:
                parts.append(option_string)
            return ((','.join(parts) + ' ') + args_string)