code: def _create_word_graph_file(name, file_storage, word_set):
      
      word_graph_file = file_storage.create_file(name)
      spelling.wordlist_to_graph_file(sorted(list(word_set)),
                                      word_graph_file)
      return copy_to_ram(file_storage).open_file(name)
docs: Create a word graph file and open it in memory.