code: def str2none(value: str):
      """
      If the value is a variant of `none`, return None.
  
      Otherwise, return the original value.
      """
      if value.lower() == "none":
          return None
      else:
          return value
  
imports: import argparse
  import importlib
  import os
  import sys
  import datetime
  import parlai
  import parlai.utils.logging
  from parlai.core.build_data import modelzoo_path
  from parlai.core.loader import load_teacher_module, load_agent_module, load_world_module
  from parlai.tasks.tasks import ids_to_tasks
  from parlai.core.opt import Opt
  from parlai.utils.io import PathManager
  from typing import List, Optional
label_desc: Use image node_id 4 for calling a global function with example usage: str2none(value) and returns: None, value