message: added one line
diff: @@ -443,6 +443,9 @@ def preprocess_input(x, data_format=None):
  Returns
  Preprocessed array.
  +
  + Raises
  + ValueError: In case of unknown `data_format` argument.
  """
  return imagenet_utils.preprocess_input(x, data_format=data_format, mode='tf')
  