code: def on_episode_created(
      self, *, worker, base_env, policies, env_index, episode, **kwargs
  ):
      print(f"Sub-env {env_index} is going to be reset.")
      self._reset_counter += 1
  
      # Make sure the passed in episode is really brand new.
      assert episode.env_id == env_index
      if isinstance(episode, Episode):
          assert episode.length == 0
          assert episode.started is False
      else:
          assert episode.length == -1
      assert episode.worker is worker
  
imports: from collections import Counter
  import unittest
  import ray
  from ray.rllib.algorithms.callbacks import DefaultCallbacks, make_multi_callbacks
  import ray.rllib.algorithms.dqn
  from ray.rllib.algorithms.ppo import PPOConfig
  from ray.rllib.evaluation.episode import Episode
  from ray.rllib.examples.env.random_env import RandomEnv
  from ray.rllib.utils.test_utils import framework_iterator
label_desc: Use image node_id 2 for calling the OnEpisodeCreatedCallback obj's underlying member method code with example usage: obj.on_episode_created() without return types