docs: def koschei_group(config, message, group=None):
      """ Particular Koschei package groups
  
      This rule limits message to particular
      `Koschei <https://apps.fedoraproject.org/koschei/>`_ groups.
      You can specify more groups separated by commas.
      """
      if not group or 'koschei' not in message['topic']:
          return False
      groups = set([item.strip() for item in group.split(',')])
      return bool(groups.intersection(message['msg'].get('groups', [])))