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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_users(self, match):
        '''Parse usernames.'''

        # Don't parse lists here
        if match.group(2) is not None:
            return match.group(0)

        mat = match.group(0)
        if self._include_spans:
            self._users.append((mat[1:], match.span(0)))
        else:
            self._users.append(mat[1:])

        if self._html:
            return self.format_username(mat[0:1], mat[1:])