python使用装饰器和线程限制函数执行时间的方法

# -*- coding: utf-8 -*-from threading import Threadimport timeclass TimeoutException(Exception):  passThreadStop = Thread._Thread__stop#获取私有函数def timelimited(timeout):  def decorator(function):    def decorator2(*args,**kwargs):      class TimeLimited(Thread):        def __init__(self,_error= None,):          Thread.__init__(self)          self._error = _error        def run(self):          try:            self.result = function(*args,**kwargs)          except Exception,e:            self._error =e        def _stop(self):          if self.isAlive():            ThreadStop(self)      t = TimeLimited()      t.start()      t.join(timeout)      if isinstance(t._error,TimeoutException):        t._stop()        raise TimeoutException('timeout for %s' % (repr(function)))      if t.isAlive():        t._stop()        raise TimeoutException('timeout for %s' % (repr(function)))      if t._error is None:        return t.result    return decorator2  return decorator@timelimited(2)def fn_1(secs):  time.sleep(secs)  return 'Finished'if __name__ == "__main__":  print fn_1(4)