Question about #python# : Why is output not in log format

Why is the output file in log format

class GetLog:
    @classmethod
    def get_log(cls):
        cls.log = None
        if cls.log is None:
            # 1.获取日志器
            cls.log = logging.getLogger()
            # 1.1获取日志器级别info
            cls.log.setLevel(logging.INFO)
            filepath = DIR_path + os.sep + "log" + os.sep + "p2p.log"
            # 2.获取处理器
            # sh = logging.StreamHandler()控制台处理器
            tf = logging.handlers.TimedRotatingFileHandler(filepath,
                                                           when="midnight",
                                                           interval=1,
                                                           backupCount=7,
                                                           encoding="UTF-8"
                                                           )  # 文件处理器
            # 3.获取格式器
            fmt = "%(asctime)s %(levelname)s [%(name)s] [%(filename)s(%(funcName)s:%(lineno)d)] - %(message)s"
            # 4.将格式器添加到处理器中
            formatter = logging.Formatter(fmt)
            tf.setFormatter(formatter)
            # 5.将处理器添加到日志器中
            cls.log.addHandler(tf)
        # 返回日志器
        return cls.log