code: def episode_mutation(self, episode: List[Message]) -> List[Message]:
      new_episodes = []
      for message in episode:
          new_message = message.copy()
          label = message["labels"][0]
          if label == "__notok__":
              label = "neg"
          else:
              label = "pos"
          new_message.force_set("labels", [label])
          new_episodes.append(new_message)
      return new_episodes
  
imports: from typing import List, Tuple
  from typing import Optional
  from parlai.core.agents import Agent, create_agent_from_model_file, create_agent_from_shared
  from parlai.core.params import ParlaiParser
  from parlai.core.message import Message
  from parlai.core.opt import Opt
  from parlai.core.mutators import register_mutator, ManyEpisodeMutator, EpisodeMutator
  import parlai.tasks.bot_adversarial_dialogue.agents
  import parlai.tasks.dialogue_safety.agents
  import parlai.utils.logging
  from parlai.core.metrics import AverageMetric
label_desc: Use image node_id 1 for calling the SafetyRelabelClassesMutator obj's underlying member method code with example usage: obj.episode_mutation(episode) and returns: new_episodes