code: def warn_once(msg: str) -> None:
      """
      Log a warning, but only once.
  
      :param str msg: Message to display
      """
      global _seen_logs
      if msg not in _seen_logs:
          _seen_logs.add(msg)
          logging.warning(msg)
  
imports: from collections import deque, OrderedDict
  from typing import Union, Optional, Set, Any, Dict, List, Tuple
  from datetime import timedelta
  import functools
  import math
  import time
  import re
  import shutil
  import json
  import os
  from parlai.core.message import Message
  from parlai.utils.strings import colorize
  from parlai.utils.io import PathManager
  import parlai.utils.logging
label_desc: Use image node_id 14 for calling a global function with example usage: warn_once(msg) without return types