code: def formatter_fields_for_record(self, record):
          
          datetime_serialized = (
              datetime.now(timezone.utc).astimezone(self.tz).isoformat()
          )
  
          default_fields = (
              (LOGGED_AT_FIELDNAME, datetime_serialized),
              (LINE_NUMBER_FIELDNAME, record.lineno),
              (FUNCTION_NAME_FIELDNAME, record.funcName),
              (LOG_LEVEL_FIELDNAME, self.level_to_name_mapping[record.levelno]),
              (FILE_PATH_FIELDNAME, record.pathname),
          )
  
          for field, value in default_fields:
              if field in self.log_fields:
                  yield field, value
docs: :type record: aiologger.loggers.json.LogRecord