code: def _init_file_logger(logger, level, log_path, log_size, log_count):
      
      if level not in [logging.NOTSET, logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL]:
          level = logging.DEBUG
  
      for h in logger.handlers:
          if isinstance(h, logging.handlers.RotatingFileHandler):
              if h.level == level:
                  return
  
      fh = logging.handlers.RotatingFileHandler(
          log_path, maxBytes=log_size, backupCount=log_count)
      fh.setLevel(level)
      fh.setFormatter(_formatter)
      logger.addHandler(fh)
docs: one logger only have one level RotatingFileHandler