How to use the jsonargparse.Path._check_mode function in jsonargparse

def __init__(self, **kwargs):
        """Initializer for ActionPathList instance.

        Args:
            mode (str): The required type and access permissions among [fdrwxcuFDRWX] as a keyword argument (uppercase means not), e.g. ActionPathList(mode='fr').
            skip_check (bool): Whether to skip path checks (def.=False).
            rel (str): Whether relative paths are with respect to current working directory 'cwd' or the list's parent directory 'list' (default='cwd').

        Raises:
            ValueError: If any of the parameters (mode or rel) are invalid.
        """
        if 'mode' in kwargs:
            _check_unknown_kwargs(kwargs, {'mode', 'skip_check', 'rel'})
            Path._check_mode(kwargs['mode'])
            self._mode = kwargs['mode']
            self._skip_check = kwargs['skip_check'] if 'skip_check' in kwargs else False
            self._rel = kwargs['rel'] if 'rel' in kwargs else 'cwd'
            if self._rel not in {'cwd', 'list'}:
                raise ValueError('rel must be either "cwd" or "list", got '+str(self._rel)+'.')
        elif '_mode' not in kwargs:
            raise ValueError('Expected mode keyword argument.')
        else:
            self._mode = kwargs.pop('_mode')
            self._skip_check = kwargs.pop('_skip_check')
            self._rel = kwargs.pop('_rel')
            kwargs['type'] = str
            super().__init__(**kwargs)