public static function removeSynonyms($extension, $headword, $synonyms)
 {
     $extension = ExtensionManager::getModel($extension);
     if (is_string($headword)) {
         $headword = $extension->getHeadwords()->andWhere(['word' => $headword])->one();
         if (!$headword) {
             return false;
         }
     }
     if ($headword instanceof \rhoone\models\Headword) {
         return $headword->removeSynonyms($synonyms);
     }
     return false;
 }