code: def get_episode_rewards(self):
      return self._episode_rewards
  
imports: from collections import deque
  import gymnasium
  from gymnasium import spaces
  import numpy
  from typing import Union
  from ray.rllib.utils.annotations import PublicAPI
  from ray.rllib.utils.images import rgb2gray, resize
label_desc: Use image node_id 4 for calling the MonitorEnv obj's underlying member method code with example usage: obj.get_episode_rewards() and returns: self