Python multiprocessing fails with PyObjC

mptest.py

import multiprocessing
import objc
from Foundation import *

class Test:
    def __init__(self):
        self.proc = multiprocessing.Process(target=self.run)
    def start(self):
        self.proc.start()
    def run(self):
        pool = NSAutoreleasePool.alloc().init()
        runloop = NSRunLoop.currentRunLoop().getCFRunLoop()
        del pool
t = Test()
t.start()