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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 afx_adam():
 """Old version - Adam."""

  hparams = transformer.transformer_base_v2()
  hparams.optimizer_adam_beta1 = 0.9
  hparams.optimizer_adam_beta2 = 0.999
  hparams.symbol_modality_num_shards = 1
  hparams.batch_size = 2048
  hparams.optimizer = "adam"
  hparams.learning_rate_schedule = (
      "constant*rsqrt_decay*linear_warmup*rsqrt_hidden_size")
  hparams.learning_rate_constant = 2.0
  return hparams