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
    ):
      
      raise NotImplementedError()
docs: Train.