def _get_matcher(self, target):
        """Get deep match."""

        if target is None:
            matcher = None
        elif isinstance(target, (str, bytes)):
            # Plain text match
            if not self.case_sensitive:
                match = target.lower()
            else:
                match = target
            matcher = functools.partial(self._match_literal, b=match)
        else:
            # File match pattern
            matcher = target.match
        return matcher
Get deep match.