code: private static function registerObserve()
      {
          $className        = 'Observer\\'.get_called_class();
          $observableEvents = [
              'creating', 'created', 'updating', 'updated',
              'deleting', 'deleted', 'saving', 'saved',
              'restoring', 'restored',
          ];
  
          if (class_exists($className)) {
              $priority = 0;
              foreach ($observableEvents as $event) {
                  if (method_exists($className, $event)) {
                      static::registerModelEvent($event, $className.'@'.$event, $priority);
                  }
              }
          }
      }
docs: 注册 Observer 命名空间下，与当前模型同名的模型观察者
  
  @return void