stompest not sending ack until python interpreter exits

Question

I have a rabbitmq queue running on its own server.

I can do sudo rabbitmqctl list_queues on this server to the number of messages on the queue.

On another server I receive 10 frames, and acknowledge them. I then check the number of messages on the queue and the number has not changed.

I then close the python interpreter and check the number of messages on the queue server, and the number has reduced by the expected amount (10). I can repeat this process many times and the same behaviour occurs.

If this is as per design, how can I make the ack happen immediately? I thought maybe there is odd behaviour in del method of the client class, but nope.

Is there some undocumented magic happening?

My "acking" code:

client = Stomp(StompConfig(uri=settings.QUEUE_SERVER))
client.connect()
client.subscribe(
    settings.INBOUND_QUEUE_NAME,
    {StompSpec.ACK_HEADER: StompSpec.ACK_CLIENT_INDIVIDUAL}
)

for each in range(10):
    frame = self.client.receiveFrame()
    self.client.ack(frame)