Return front, attrs, close, text 4-tuple result of parsing XML element
        string *line*.

def _parse_line(cls, line):
        """
        Return front, attrs, close, text 4-tuple result of parsing XML element
        string *line*.
        """
        match = cls._xml_elm_line_patt.match(line)
        front, attrs, close, text = [match.group(n) for n in range(1, 5)]
        return front, attrs, close, text