Signal handler doesn`t handle any signals while main thread is blocked

Hi!
I waste a lot of my time figuring why this snip of code doesn`t work.
And still without any solution ;/
Does anybody know why this handler cannot handle SIGINT signal? What
did I wrong?

Thanks in advance.

#
# CODE
#
import signal
from threading import *

def siginthandler(signum, frame):
* * *global work,cv
* * *print 'terminating...'
* * *cv.acquire()
* * *work = 0
* * *cv.notifyAll ()
* * *cv.release()

work = 1
signal.signal (signal.SIGINT, siginthandler)

print 'wait for SIGINT signal'
cv = Condition ()
cv.acquire()
while work:
* * print 'waiting...'
* * cv.wait()
print 'woke up'
cv.release()

print 'terminated'