code: def get_metrics(self):
      metrics = defaultdict(list)
      monitor = get_wrapper_by_cls(self.env, MonitorEnv)
      if monitor is not None:
          for (
              episode_rewards,
              episode_steps,
          ) in monitor.next_episode_results():
              metrics["episode_rewards"].append(episode_rewards)
              metrics["episode_steps"].append(episode_steps)
      return metrics
  
file_path: PARL/benchmark/fluid/GA3C/actor.py
imports: import gym
  import numpy
  import parl
  from parl.env.atari_wrappers import wrap_deepmind, MonitorEnv, get_wrapper_by_cls
  from collections import defaultdict
label_desc: Use image node_id 4 for calling the Actor obj's underlying member method code with example usage: obj.get_metrics() and returns: metrics