docs: def convert(outputfile, inputfile, to_format, from_format):
      """
      Convert pretrained word embedding file in one format to another.
      """
      emb = word_embedding.WordEmbedding.load(
          inputfile, format=_input_choices[from_format][1],
          binary=_input_choices[from_format][2])
      emb.save(outputfile, format=_output_choices[to_format][1],
               binary=_output_choices[to_format][2])