Try the code with multiprocessing

gistfile1.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-

from multiprocessing import Process
from multiprocessing import Queue
from multiprocessing import Pool
import multiprocessing

path_list = range(10)
bad_path_list = []

def add_to_bad_path_list(bad_path, lock):
    lock.acquire()
    print "%s is added." % str(bad_path)
    global bad_path_list
    bad_path_list.append(bad_path)
    print bad_path_list
    lock.release()

def check_path(path_list_q, lock): #对目标队列进行检查，条件简化为3的倍数
    while True:
        if not path_list_q.empty():
            value = path_list_q.get()
            if 0 == value % 3:
                add_to_bad_path_list(value, lock)
        else:
            break

if __name__ == '__main__':
    manager = multiprocessing.Manager()

    path_list_q = manager.Queue()

    for i in path_list: #初始化待检查队列
        path_list_q.put(i)

    lock = manager.Lock()
    p = Pool()
    p1 = p.apply_async(check_path, args=(path_list_q, lock))
    p.close()
    p.join()

    print bad_path_list
    print 'Done.'

What's wrong with my code? Why print bad_path_list as [] finally?