class_docstr: Env wrapper that keeps tracks of total raw episode rewards, length of raw episode rewards for evaluation.
      
class_docstr_tok: ["Env","wrapper","that","keeps","tracks","of","total","raw","episode","rewards",",","length","of","raw","episode","rewards","for","evaluation","."]
code: def update(self, ob, rew, done, info):
      self.rewards.append(rew)
      if done:
          eprew = sum(self.rewards)
          eplen = len(self.rewards)
          epinfo = {
              "r": round(eprew, 6),
              "l": eplen,
              "t": round(time.time() - self.tstart, 6),
          }
          assert isinstance(info, dict)
          info["episode"] = epinfo
          self.reset()
  
imports: import numpy
  import gym
  import time
  from parl.env.compat_wrappers import CompatWrapper
label_desc: Use image node_id 3 for calling the MonitorEnv obj's underlying member method code with example usage: obj.update(ob, rew, done, info) without return types