How to use the pathspec.util function in pathspec

Compiles the pattern lines.

		*pattern_factory* can be either the name of a registered pattern
		factory (:class:`str`), or a :class:`~collections.abc.Callable` used
		to compile patterns. It must accept an uncompiled pattern (:class:`str`)
		and return the compiled pattern (:class:`.Pattern`).

		*lines* (:class:`~collections.abc.Iterable`) yields each uncompiled
		pattern (:class:`str`). This simply has to yield each line so it can
		be a :class:`file` (e.g., from :func:`open` or :class:`io.StringIO`)
		or the result from :meth:`str.splitlines`.

		Returns the :class:`PathSpec` instance.
		"""
		if isinstance(pattern_factory, string_types):
			pattern_factory = util.lookup_pattern(pattern_factory)
		if not callable(pattern_factory):
			raise TypeError("pattern_factory:{!r} is not callable.".format(pattern_factory))

		if not util._is_iterable(lines):
			raise TypeError("lines:{!r} is not an iterable.".format(lines))

		lines = [pattern_factory(line) for line in lines if line]
		return cls(lines)