code: def _check_last_values(self, episode):
      last_obs = {
          k: np.where(v)[0].item()
          for k, v in episode._agent_to_last_obs.items()
      }
      last_raw_obs = episode._agent_to_last_raw_obs
      last_info = episode._agent_to_last_info
      last_terminated = episode._agent_to_last_terminated
      last_truncated = episode._agent_to_last_truncated
      last_action = episode._agent_to_last_action
      last_reward = {
          k: v[-1] for k, v in episode._agent_reward_history.items()
      }
      if self.step == 0:
          for last in [
              last_obs,
              last_terminated,
              last_truncated,
              last_action,
              last_reward,
          ]:
              self.tc.assertEqual(last, {})
          self.tc.assertTrue("__common__" in last_info)
          self.tc.assertTrue(len(last_raw_obs) > 0)
          for agent in last_raw_obs.keys():
              index = int(str(agent).replace("agent", ""))
              self.tc.assertEqual(last_raw_obs[agent], 0)
              self.tc.assertEqual(
                  last_info[agent]["timestep"], self.step + index
              )
      else:
          for agent in last_obs.keys():
              index = int(str(agent).replace("agent", ""))
              self.tc.assertEqual(last_obs[agent], self.step + index)
              self.tc.assertEqual(last_reward[agent], self.step + index)
              self.tc.assertEqual(
                  last_terminated[agent], self.step == NUM_STEPS
              )
              self.tc.assertEqual(
                  last_truncated[agent], self.step == NUM_STEPS
              )
              if self.step == 1:
                  self.tc.assertEqual(last_action[agent], 0)
              else:
                  self.tc.assertEqual(
                      last_action[agent], self.step + index - 1
                  )
              self.tc.assertEqual(
                  last_info[agent]["timestep"], self.step + index
              )
  
imports: import ray
  import unittest
  from typing import Dict, List, Optional, Union, Tuple
  import numpy
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.algorithms.callbacks import DefaultCallbacks
  from ray.rllib.env.multi_agent_env import MultiAgentEnv
  from ray.rllib.evaluation.rollout_worker import RolloutWorker
  from ray.rllib.evaluation.episode import Episode
  from ray.rllib.examples.env.mock_env import MockEnv3
  from ray.rllib.policy import Policy
  from ray.rllib.utils import override
  from ray.rllib.utils.typing import TensorStructType, TensorType
label_desc: Use image node_id 5 for calling the LastInfoCallback obj's underlying member method code with example usage: obj._check_last_values(episode) without return types