How to use the pathspec.util.normalize_files function in pathspec

*files* (:class:`~collections.abc.Iterable` of :class:`str; or
		:class:`pathlib.PurePath`) contains the file paths to be matched
		against :attr:`self.patterns `.

		*separators* (:class:`~collections.abc.Collection` of :class:`str`;
		or :data:`None`) optionally contains the path separators to
		normalize. See :func:`~pathspec.util.normalize_file` for more
		information.

		Returns the matched files (:class:`~collections.abc.Iterable` of
		:class:`str`).
		"""
		if not util._is_iterable(files):
			raise TypeError("files:{!r} is not an iterable.".format(files))

		file_map = util.normalize_files(files, separators=separators)
		matched_files = util.match_files(self.patterns, iterkeys(file_map))
		for path in matched_files:
			yield file_map[path]