Traceback if parser detects an illegal character

A traceback error is raised in parser.py if it detects an illegal character. The problem is in the code in parser.py around line 129:

    def t_error(self, token):
        position = Position(self._input_name,
                            self._lexer.lineno,
                            self._lexer.lexpos)
        raise ParsingError('Illegal character %r' % token.value[0], position)

    ==> error, class lexer has no attribute _input_name

As far as I have seen, only the parser has the member _input_name, but
currently not the lexer.