parse the given ASCII BASIC listing.
        Return a ParsedBASIC() instance.

def parse(self, ascii_listing):
        """
        parse the given ASCII BASIC listing.
        Return a ParsedBASIC() instance.
        """
        self.parsed_lines = ParsedBASIC()
        for match in self.regex_line_no.finditer(ascii_listing):
            log.info("_" * 79)
            log.info("parse line >>>%r<<<", match.group())
            line_no = int(match.group("no"))
            line_content = match.group("content")

            self.line_data = []
            self._parse_code(line_content)
            log.info("*** line %s result: %r", line_no, self.line_data)

            self.parsed_lines[line_no] = self.line_data

        return self.parsed_lines