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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 train_agent_real_env(env, learner, hparams, epoch):
 """Train the PPO agent in the real environment."""

  base_algo_str = hparams.base_algo

  train_hparams = trainer_lib.create_hparams(hparams.base_algo_params)
  rl_utils.update_hparams_from_hparams(
      train_hparams, hparams, "real_" + base_algo_str + "_"
  )
  if hparams.wm_policy_param_sharing:
    train_hparams.optimizer_zero_grads = True

  env_fn = rl.make_real_env_fn(env)
  num_env_steps = real_env_step_increment(hparams)
  learner.train(
      env_fn,
      train_hparams,
      simulated=False,
      save_continuously=False,
      epoch=epoch,
      sampling_temp=hparams.real_sampling_temp,
      num_env_steps=num_env_steps,
  )
  # Save unfinished rollouts to history.
  env.reset()