def str_to_int(arg, queue):
    result = int(arg)
    queue.put({arg: result})

def combine():
    arguments = ('111', '222', '333')
    q = Queue.Queue()
    threads = []

    for argument in arguments:
        t = Thread(target=str_to_int, args=(argument, q))
        t.start()
        threads.append(t)

    for t in threads:
        t.join()

    return [q.get() for _ in xrange(len(arguments))]