code: def create_sequence_readers(sources: List[str], target: str,
                              vocab_sources: List[vocab.Vocab],
                              vocab_target: vocab.Vocab) -> Tuple[List[SequenceReader], SequenceReader]:
      
      source_sequence_readers = [SequenceReader(source, vocab, add_eos=True) for source, vocab in
                                 zip(sources, vocab_sources)]
      target_sequence_reader = SequenceReader(target, vocab_target, add_bos=True)
      return source_sequence_readers, target_sequence_reader
docs: Create source readers with EOS and target readers with BOS.
  
      :param sources: The file names of source data and factors.
      :param target: The file name of the target data.
      :param vocab_sources: The source vocabularies.
      :param vocab_target: The target vocabularies.
      :return: The source sequence readers and the target reader.