message: Update load.py
  Add a warning when fitting models loaded from SaveModel having optimizers  with slots.
  Ref:
diff: @@ -129,6 +129,9 @@ def load(path, compile=True, options=None): # pylint: disable=redefined-builtin
  model.compile(**saving_utils.compile_args_from_training_config(
  training_config))
  saving_utils.try_build_compiled_arguments(model)
  + if(model.optimizer.get_slot_names()):
  + model._saved_model_with_slot = True
  +
  else:
  logging.warning('No training configuration found in save file, so the '
  'model was *not* compiled. Compile it manually.')
  