How to exit netfilter block?

[Pooshkis]

I'm running this code:

import os, sys

queue = NetfilterQueue()
QUEUE_NUM1 = 1

def changing_payload(pkt):
    global binary_rep
    if len(binary_rep) == 0:
         raise KeyboardInterrupt
    print(binary_rep)
    binary_rep = binary_rep[1:]
    

binary_rep = "0101000021002220201551051101545"

try:
    os.system("iptables -I OUTPUT -d 10.0.1.0/24 -p udp --dport 7078 -j NFQUEUE --queue-num {}".format(QUEUE_NUM1))
    queue.bind(QUEUE_NUM1, changing_payload)
    queue.run()
except KeyboardInterrupt:
    queue.unbind()
    os.system("iptables --flush")
    print('Message sent..')

and get error message but netfilterqueue que is still running:

Traceback (most recent call last):
  File "/home/nfq.py", line 10, in changing_payload
    raise KeyboardInterrupt("Should stop")
KeyboardInterrupt: Should stop

Any ideas how could I stop netfilterqueue without exiting program? (BTW pressing "CTRL+C" isn't working too)