code: def sync_lists(self):
          
          if self._sync_lists is None:
              self._sync_lists = SyncListList(self._version, service_sid=self._solution['sid'], )
          return self._sync_lists
docs: Access the sync_lists
  
          :returns: twilio.rest.sync.v1.service.sync_list.SyncListList
          :rtype: twilio.rest.sync.v1.service.sync_list.SyncListList