public function byLanguage($language = null)
    {
        if (!$language) {
            if (Yii::$app->id === 'app-backend') {
                $language = Yii::$app->wavecms->editedLanguage;
            } else {
                $language = Yii::$app->language;
            }
        }

        return $this->andWhere(['REGEXP', News::tableName() . '.languages', '(^|;)(' . $language . ')(;|$)']);
    }