protected function _post_update()
 {
     parent::_post_update();
     if (isset($this->index_object)) {
         $members = $this->_pre_update($this->members);
         foreach ($members as $trigger_resource) {
             $this->_CI_load('library', 'kals_actor/User', 'user');
             $association_user = $trigger_resource->get_user();
             $trigger_actor = $this->index_object->get_user();
             $this->_CI_load('library', 'kals_actor/Notification_responded', 'notification_responded');
             $notification = $this->CI->notification_responded->create_notification($association_user, $trigger_resource, $trigger_actor);
             if (is_null($notification)) {
                 handle_error($this->lang->line('notification.responded.create_notification.exception'));
             }
         }
         //foreach($members AS $trigger_resource)
     }
     //if (isset($index_id))
     return $this;
 }