#对之前文件进行的增删改查操作实现日志操作，日志输出用户进行过的操作。def log():    import logging    logger_obj=logging.getLogger()    logger_obj.setLevel(logging.INFO)    fh=logging.FileHandler('log.txt')    ch=logging.StreamHandler()    logger_obj.addHandler(fh)    logger_obj.addHandler(ch)    formatter = logging.Formatter('%(asctime)s - %(name)s - %(message)s')    fh.setFormatter(formatter)    ch.setFormatter(formatter)    return logger_objlogger=log()     #函数赋值给变量，可以随意调用。# logger.debug('*****************')# logger.info('this is adding operation ')# logger.warning('this is delete operation')# logger.error('this is changing operation')# logger.critical('this is scaning operation')def add():    logger.info('this is adding operation ')    passdef delete():    logger.warning('this is delete operation')    passdef change():    logger.error('this is changing operation')    passdef scan():    logger.critical('this is scaning operation')    passadd()delete()change()scan()