message: Add raise list to DenseNet models
diff: @@ -464,6 +464,12 @@ DOC = """
  >>>model.name
  'densenet201'
  + Raises:
  + ValueError: in case of invalid argument for `weights`,
  + or invalid input shape.
  + ValueError: if `classifier_activation` is not `softmax` or `None` when
  + using a pretrained top layer.
  +
  """
  setattr(DenseNet121, '__doc__', DenseNet121.__doc__ + DOC)
  