public function findModel($id, $slug = '')
    {
        if($this->_model === null) 
        {
            if(($this->_model = $id ? Post::findOne($id) : Post::findOne(['slug' => $slug])) !== null) 
            {
                return $this->_model;
            } else {
                throw new NotFoundHttpException(Module::t('core', 'The requested model does not exist.'));
            }
        }
    }