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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _parse_lists(self, match):
        '''Parse lists.'''

        # Don't parse usernames here
        if match.group(4) is None:
            return match.group(0)

        pre, at_char, user, list_name = match.groups()
        list_name = list_name[1:]
        if self._include_spans:
            self._lists.append((user, list_name, match.span(0)))
        else:
            self._lists.append((user, list_name))

        if self._html:
            return '%s%s' % (pre, self.format_list(at_char, user, list_name))