code: def enable_aggregate_mode(self, mode, interfaces):
          
          if mode in ['lb', 'ha']:
              self.data['aggregate_mode'] = mode
              self.data['second_interface_id'] = ','.join(map(str, interfaces))   
              self.save()
docs: Enable Aggregate (LAGG) mode on this interface. Possible LAGG
          types are 'ha' and 'lb' (load balancing). For HA, only one
          secondary interface ID is required. For load balancing mode, up
          to 7 additional are supported (8 max interfaces).
          
          :param str mode: 'lb' or 'ha'
          :param list interfaces: secondary interfaces for this LAGG
          :type interfaces: list(str,int)
          :raises UpdateElementFailed: failed adding aggregate
          :return: None