how to get the return value of a thread?

[Leo Jay]

Dear all,

i would like to get the return value of all threads

e.g.
def foo(num):
    if num>10:
        return 1
    elif num>50:
        return 2
    else
        return 0


after i invoked 
t = thread.start_new_thread(foo,(12,))
how to get the return value of `foo'?

Thanks

-- 
Best Regards,
Leo Jay