public function getSitetreeManager()
    {    
        if (empty(static::$_sitetreeManager)) {
            $module = Yii::$app->getModule($this->sitetreeModuleUniqueId);
            if (!empty($module) && $module instanceof UniModule) {
                $mgr = $module->getDataModel($this->sitetreeManagerAlias);
                if (empty($mgr->rules)) $mgr->rules = Yii::$app->urlManager->rules;
                static::$_sitetreeManager = $mgr;
            }
        }
        return static::$_sitetreeManager;
    }