code: def step(self, action):
      ob, reward, terminated, truncated, info = self.env.step(action)
      self.frames.append(ob)
      return self._get_ob(), reward, terminated, truncated, info
  
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 3 for calling the FrameStack obj's underlying member method code with example usage: obj.step(action) and returns: self,  reward,  terminated,  truncated,  info