Logic is not clear

[nshmyrev]

  create_vocabulary(ph_vocab_path, train_ph)
  create_vocabulary(gr_vocab_path, train_gr)

  # Initialize vocabularies.
  ph_vocab = initialize_vocabulary(ph_vocab_path, False)
  gr_vocab = initialize_vocabulary(gr_vocab_path, False)

Why do you need to initialize the vocabulary after you created it. Logic must be more straightforward. First initialize the vocabulary, then save it, then there is no need to reload it again.

[nshmyrev]

Save must be separate

[nshmyrev]

create_vocabulary should create a vocabulary, not a list

save_vocabulary should save vocabulary, not a list