code: def _persistent_memory_past_messages(
      self, task_state: TaskState
  ) -> List[Message]:
      if self.last_interaction is None:
          return task_state.messages
  
      #   Check if task_state matches our last interaction
      interaction = self.last_interaction
      task_state_message_ix = 0
      for our_message_ix in range(0, len(interaction.messages)):
          if our_message_ix in interaction.private_messages_ids:
              continue
          else:
              if (
                  task_state.messages[task_state_message_ix]
                  != interaction.messages[our_message_ix]
              ):
                  raise ValueError(
                      (
                          f"task_state message {task_state_message_ix} different than the corresponding message "
                          "in the interaction history. "
                          "Such scenario is not supported by a CoT solver with peristent_memory = True"
                      )
                  )
              task_state_message_ix += 1
  
      #   Everything's fine!
      return (
          interaction.messages
          + task_state.messages[task_state_message_ix:]
      )
  
file_path: evals/evals/solvers/openai_chat_completion_cot_solver.py
imports: from dataclasses import dataclass
  from typing import Any, Dict, List, Union
  from evals.completion_fns.openai import OpenAIChatCompletionFn
  from evals.solvers.prompts.cot import DEFAULT_COT_TEMPLATE, DEFAULT_EXTRACT_ANSWER_TEMPLATE
  from evals.solvers.solver import OpenAISolver, SolverResult
  from evals.task_state import Message, TaskState
label_desc: Use image node_id 4 for calling the OpenAIChatCompletionCoTSolver obj's underlying member method code with example usage: obj._persistent_memory_past_messages(task_state) and returns: unknown, task_state