docs: def _get_sorted_inputs(filename):
    """Read and sort lines from the file sorted by decreasing length.
  
    Args:
      filename: String name of file to read inputs from.
    Returns:
      Sorted list of inputs, and dictionary mapping original index->sorted index
      of each element.
    """
    with tf.gfile.Open(filename) as f:
      records = f.read().split("\n")
      inputs = [record.strip() for record in records]
      if not inputs[-1]:
        inputs.pop()
  
    input_lens = [(i, len(line.split())) for i, line in enumerate(inputs)]
    sorted_input_lens = sorted(input_lens, key=lambda x: x[1], reverse=True)
  
    sorted_inputs = []
    sorted_keys = {}
    for i, (index, _) in enumerate(sorted_input_lens):
      sorted_inputs.append(inputs[index])
      sorted_keys[index] = i
    return sorted_inputs, sorted_keys