code: def _add_pret_words(self, pret_embeddings):
          
          words_in_train_data = set(self._id2word)
          pret_embeddings = gluonnlp.embedding.create(pret_embeddings[0], source=pret_embeddings[1])
  
          for idx, token in enumerate(pret_embeddings.idx_to_token):
              if token not in words_in_train_data:
                  self._id2word.append(token)
docs: Read pre-trained embedding file for extending vocabulary
  
          Parameters
          ----------
          pret_embeddings : tuple
              (embedding_name, source), used for gluonnlp.embedding.create(embedding_name, source)