code: def _logged_once(self, msg, mode):
      PREFIX_LEN = 12
      if mode == LogMode.ONCE:
          if msg[PREFIX_LEN:] in self.once_logged:
              return True
          self.once_logged.add(msg[PREFIX_LEN:])
      return False
  
imports: import enum
  import logging
  import sys
  import threading
  import warnings
  from contextlib import contextmanager
  from logging.handlers import MemoryHandler
  from nemo.constants import NEMO_ENV_VARNAME_REDIRECT_LOGS_TO_STDERR, NEMO_ENV_VARNAME_TESTING
  from nemo.utils.env_var_parsing import get_envbool
  from nemo.utils.formatters.base import BaseNeMoFormatter, DebugNeMoFormatter
  from nemo.utils.get_rank import is_global_rank_zero
  from nemo.utils.metaclasses import Singleton
label_desc: Use image node_id 17 for calling the Logger obj's underlying member method code with example usage: obj._logged_once(msg, mode) and returns: False, True