python多进程问题

[lovesdan]

有这样一段代码

def worker(download_url=("", ""), queue=None):
    queue.put((download_url, 'start'))
    if os.path.exists(download_url[0]):
        return
    urllib.urlretrieve(download_url[1], download_url[0] + ".tmp", callback)
    os.rename(download_url[0] + ".tmp", download_url[0])
    queue.put((download_url, 'end'))


def callback(block, block_size, file_size):
    if -1 != file_size:
        per = int(100.0 * block * block_size / file_size)
        if per > 100:
            per = 100
if __name__ == '__main__':
   mManager = multiprocessing.Manager()
   mQueue = mManager.Queue()
   pool = multiprocessing.Pool(self.mProgressNum)
   for _list in mDownload_list:
        Result.append(self.pool.apply_async(worker, (_list, mQueue,)))
        self.pool.close()
        self.pool.join()

有什么办法可以让我主线程获取到callback的数据