public static function handleMissingTranslation(MissingTranslationEvent $event)
 {
     $fallbackTranslation = SourceMessage::getMessageTranslation($event->category, $event->message, Yii::$app->params['fallbackLanguage']);
     if (isset($fallbackLanguage) && !empty($fallbackLanguage->translation)) {
         return $event->translatedMessage = $fallbackLanguage->translation;
     }
     $mainLanguageTranslation = SourceMessage::getMessageTranslation($event->category, $event->message, Yii::$app->params['appMainLanguage']);
     if (isset($mainLanguageTranslation) && !empty($mainLanguageTranslation->translation)) {
         return $event->translatedMessage = $mainLanguageTranslation->translation;
     }
 }