Python编程：signal处理超时问题

# -*- coding: utf-8 -*-
import signal
import time
def handle(signum, frame):
    print("超时了")
# 注册信号
signal.signal(signal.SIGALRM, handle)
# 设置信号发送时间
signal.alarm(3)  # 开启闹钟信号
print("开启信号")
time.sleep(5)
print("关闭信号")
signal.alarm(0)  # 关闭闹钟信号
"""
sleep 2
开启信号
关闭信号
sleep 5
开启信号
超时了
关闭信号
"""

import signal
class TimeOutException(Exception):
    pass
def handle(signum, frame):
    raise TimeOutException("运行超时！")
def set_timeout(timeout, callback):
    def wrapper(func):
        def inner(*args, **kwargs):
            try:
                signal.signal(signal.SIGALRM, handle)
                signal.alarm(timeout)  # 开启闹钟信号
                rs = func(*args, **kwargs)
                signal.alarm(0)  # 关闭闹钟信号
                return rs
            except TimeOutException as e:
                callback()
        return inner
    return wrapper
def process_time():
    print("超时了")
@set_timeout(40, process_time)
def function():
  pass