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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def layer_stack_from_hparams(hparams, prefix):
 """Create a layer stack based on the hyperparameter values."""

  layers = hparams.get(prefix + "layers")
  return transformer.LayerStack(
      [layers_registry[l](hparams, prefix) for l in layers],
      dropout_rate=hparams.layer_prepostprocess_dropout,
      norm_epsilon=hparams.norm_epsilon)