паб / подписка с нулевым размером mq с неработающим multipart

Вот мой сценарий.

#!/usr/bin/env python

import traceback
import sys
import zmq
from time import sleep

print "Creating the zmq.Context"
context = zmq.Context()

print "Binding the publisher to the local socket at port 5557"
sender = context.socket(zmq.PUB)
sender.bind("tcp://*:5557")

print "Binding the subscriber to the local socket at port 5557"
receiver = context.socket(zmq.SUB)
receiver.connect("tcp://*:5557")

print "Setting the subscriber option to get only those originating from \"B\""
receiver.setsockopt(zmq.SUBSCRIBE, "B")

print "Waiting a second for the socket to be created."
sleep(1)

print "Sending messages"
for i in range(1,10):
    msg = "msg %d" % (i)
    env = None
    if i % 2 == 0:
        env = ["B", msg]
    else:
        env = ["A", msg]
    print "Sending Message:  ", env
    sender.send_multipart(env)

print "Closing the sender."
sender.close()

failed_attempts = 0
while failed_attempts < 3:
    try:
        print str(receiver.recv_multipart(zmq.NOBLOCK))
    except:
        print traceback.format_exception(*sys.exc_info())
        failed_attempts += 1 

print "Closing the receiver."
receiver.close()

print "Terminating the context."
context.term()

"""
Output:

Creating the zmq.Context
Binding the publisher to the local socket at port 5557
Binding the subscriber to the local socket at port 5557
Setting the subscriber option to get only those originating from "B"
Waiting a second for the socket to be created.
Sending messages
Sending Message:   ['A', 'msg 1']
Sending Message:   ['B', 'msg 2']
Sending Message:   ['A', 'msg 3']
Sending Message:   ['B', 'msg 4']
Sending Message:   ['A', 'msg 5']
Sending Message:   ['B', 'msg 6']
Sending Message:   ['A', 'msg 7']
Sending Message:   ['B', 'msg 8']
Sending Message:   ['A', 'msg 9']
Closing the sender.
['B', 'msg 2']
['B', 'msg 4']
['B', 'msg 6']
['B', 'msg 8']
['Traceback (most recent call last):\n', '  File "./test.py", line 43, in \n    print str(receiver.recv_multipart(zmq.NOBLOCK))\n', '  File "socket.pyx", line 611, in zmq.core.socket.Socket.recv_multipart (zmq/core/socket.c:5181)\n', '  File "socket.pyx", line 514, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4811)\n', '  File "socket.pyx", line 548, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4673)\n', '  File "socket.pyx", line 99, in zmq.core.socket._recv_copy (zmq/core/socket.c:1344)\n', 'ZMQError: Resource temporarily unavailable\n']
['Traceback (most recent call last):\n', '  File "./test.py", line 43, in \n    print str(receiver.recv_multipart(zmq.NOBLOCK))\n', '  File "socket.pyx", line 611, in zmq.core.socket.Socket.recv_multipart (zmq/core/socket.c:5181)\n', '  File "socket.pyx", line 514, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4811)\n', '  File "socket.pyx", line 548, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4673)\n', '  File "socket.pyx", line 99, in zmq.core.socket._recv_copy (zmq/core/socket.c:1344)\n', 'ZMQError: Resource temporarily unavailable\n']
['Traceback (most recent call last):\n', '  File "./test.py", line 43, in \n    print str(receiver.recv_multipart(zmq.NOBLOCK))\n', '  File "socket.pyx", line 611, in zmq.core.socket.Socket.recv_multipart (zmq/core/socket.c:5181)\n', '  File "socket.pyx", line 514, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4811)\n', '  File "socket.pyx", line 548, in zmq.core.socket.Socket.recv (zmq/core/socket.c:4673)\n', '  File "socket.pyx", line 99, in zmq.core.socket._recv_copy (zmq/core/socket.c:1344)\n', 'ZMQError: Resource temporarily unavailable\n']
Closing the receiver.
Terminating the context.
"""

И вопрос в том ... почему этот код не работает?

[EDIT] Получив сверхбыстрый ответ в списке рассылки zeromq, я обновил приведенный выше код.