class_docstr: API for policy learners.
docstr: Train.
docstr_tok: ["Train","."]
code: def train(
      self,
      env_fn,
      hparams,
      simulated,
      save_continuously,
      epoch,
      sampling_temp=1.0,
      num_env_steps=None,
      env_step_multiplier=1,
      eval_env_fn=None,
      report_fn=None,
  ):
      """Train."""
      raise NotImplementedError()
  
file_path: tensor2tensor/tensor2tensor/rl/policy_learner.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
label_desc: Use image node_id 2 for calling the PolicyLearner obj's underlying member method code with example usage: obj.train(env_fn, hparams, simulated, save_continuously, epoch, sampling_temp, num_env_steps, env_step_multiplier, eval_env_fn, report_fn) without return types