code: def __init__(self, episode_length, num):
      super().__init__()
      self._skip_env_checking = True
      self.agents = [MockEnv3(episode_length) for _ in range(num)]
      self.terminateds = set()
      self.truncateds = set()
      self.observation_space = self.agents[0].observation_space
      self.action_space = self.agents[0].action_space
  
imports: import unittest
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.env.multi_agent_env import MultiAgentEnv
  from ray.rllib.evaluation.rollout_worker import RolloutWorker
  from ray.rllib.examples.env.mock_env import MockEnv3
  from ray.rllib.policy import Policy
  from ray.rllib.utils import override
label_desc: Use image node_id 1 to create a new EpisodeEnv object from inherited base classes: MultiAgentEnv with example: obj = EpisodeEnv(episode_length, num)