code: def get_metrics(self):
      metrics = defaultdict(list)
      for env in self.envs:
          monitor = get_wrapper_by_cls(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/A2C/actor.py
imports: import gym
  import numpy
  import parl
  from atari_model import AtariModel
  from collections import defaultdict
  from atari_agent import AtariAgent
  from parl.env.atari_wrappers import wrap_deepmind, MonitorEnv, get_wrapper_by_cls
  from parl.env.vector_env import VectorEnv
  from parl.utils.rl_utils import calc_gae
label_desc: Use image node_id 3 for calling the Actor obj's underlying member method code with example usage: obj.get_metrics() and returns: metrics