code: def load_dataset(data_name):
      
      if data_name == 'MR' or data_name == 'Subj':
          train_dataset, output_size = _load_file(data_name)
          vocab, max_len = _build_vocab(data_name, train_dataset, [])
          train_dataset, train_data_lengths = _preprocess_dataset(train_dataset, vocab, max_len)
          return vocab, max_len, output_size, train_dataset, train_data_lengths
      else:
          train_dataset, test_dataset, output_size = _load_file(data_name)
          vocab, max_len = _build_vocab(data_name, train_dataset, test_dataset)
          train_dataset, train_data_lengths = _preprocess_dataset(train_dataset, vocab, max_len)
          test_dataset, test_data_lengths = _preprocess_dataset(test_dataset, vocab, max_len)
          return vocab, max_len, output_size, train_dataset, train_data_lengths, test_dataset, \
                 test_data_lengths
docs: Load sentiment dataset.