如下所示：
# coding=utf-8
import signal
import time
def set_timeout(num, callback):
def wrap(func):
def handle(signum, frame): # 收到信号 SIGALRM 后的回调函数，第一个参数是信号的数字，第二个参数是the interrupted stack frame.
raise RuntimeError
def to_do(*args, **kwargs):
try:
signal.signal(signal.SIGAL
