def unify(self, result):
        '''
        While comments as a list are allowed,
        comments needs to be strings for backward compatibility.
        See such claim here: https://github.com/saltstack/salt/pull/43070

        Rules applied:
          - 'comment' is joined into a multi-line string, in case the value is a list.
          - 'result' should be always either True, False or None.

        :param result:
        :return:
        '''
        if isinstance(result.get('comment'), list):
            result['comment'] = u'\n'.join([
                salt.utils.stringutils.to_unicode(elm) for elm in result['comment']
            ])
        if result.get('result') is not None:
            result['result'] = bool(result['result'])

        return result