message: Fix model_to_dot() for Sequential models
  The model_to_dot() function does not display the input layer of Sequential models correctly. See
  This fix seems to have been applied already in keras-team/keras, but not in tf.keras.
diff: @@ -77,7 +77,7 @@ def model_to_dot(model, show_shapes=False, show_layer_names=True, rankdir='TB'):
  if isinstance(model, Sequential):
  if not model.built:
  model.build()
  - layers = model.layers
  + layers = model._layers
  # Create graph nodes.
  for layer in layers:
  