multiprocessing.Queue() 和 Queue.Queue() 有区别吗？

用法都一样， 但下面这段代码，Queue从 Queue.Queue导入，read函数便没有执行

from multiprocessing import Pool, Process, Queue
import os, time, random

def write(q):
for v in ['A', 'B', 'C']:
print 'Put %s to queue ' % v
q.put_nowait(v)
time.sleep(random.random())

def read(q):
while 1:
if not q.empty():
v = q.get(True)
print "Get %s from queue" % v
time.sleep(random.random())
else:
break

if __name__ == '__main__':
q = Queue()
pw = Process(target=write, args=(q, ))
pr = Process(target=read, args=(q, ))
pw.start()
pw.join()

pr.start()
pr.join()

print "all done.."