code: def _fetch_atari_metrics(base_env):
      
      unwrapped = base_env.get_unwrapped()
      if not unwrapped:
          return None
      atari_out = []
      for u in unwrapped:
          monitor = get_wrapper_by_cls(u, MonitorEnv)
          if not monitor:
              return None
          for eps_rew, eps_len in monitor.next_episode_results():
              atari_out.append(RolloutMetrics(eps_len, eps_rew, {}, {}, {}))
      return atari_out
docs: Atari games have multiple logical episodes, one per life.
  
      However for metrics reporting we count full episodes all lives included.