def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def __init__(
        self,
        dirpath: Optional[Union[str, Path]] = None,
        filename: Optional[str] = None,
    ) -> None:
        self.dirpath = dirpath
        self.filename = filename

        self._output_file: Optional[TextIO] = None
        self._write_stream: Optional[Callable] = None
        self._local_rank: Optional[int] = None
        self._log_dir: Optional[str] = None
        self._stage: Optional[str] = None