/**
  * Deletes all terms of given vocabularies.
  *
  * @param array $vids
  *   Array of vocabulary vid.
  */
 protected function deleteVocabularyTerms($vids)
 {
     $tids = $this->vocabularyStorage->getToplevelTids($vids);
     $terms = $this->termStorage->loadMultiple($tids);
     $this->termStorage->delete($terms);
 }