I’m new with Python and I’m trying to write a sample program using pyVoIP that waits for an incoming call, reads the calling number, terminates the call and calls it back.
This is the code:

from pyVoIP.VoIP import VoIPPhone, CallState, InvalidStateError

anum = ''

def answer(call): # This will be your callback function for when you receive a phone call

   try:
     print(call.state)
     anum = call.request.headers["From"]["number"]
     call.answer()
     call.hangup()
   except InvalidStateError:
     pass

if __name__ == "__main__":
   vp = VoIPPhone('79.98.45.133',5060,'0662279775','065+eMl6Ttd6$T',callCallback=answer)
   vp.start()
#   call = vp.call('+393292100441')
   print(vp._status)
   print(CallState)
   input("Press enter to disable the phone")
   call = vp.call(anum)
   vp.stop()

The registration is ok, I succeded in getting the calling number but I get the following error:

Exception in thread SIP Recieve:
Traceback (most recent call last):
  File "/home/gtorassa/pyVoIP/projects/qosroaming/.venv/lib/python3.11/site-packages/pyVoIP/util.py", line 17, in acquired_lock_and_unblocked_socket
    socket.setblocking(False)
OSError: [Errno 9] Bad file descriptor

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.11/threading.py", line 1038, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.11/threading.py", line 1394, in run
    self.function(*self.args, **self.kwargs)
  File "/home/gtorassa/pyVoIP/projects/qosroaming/.venv/lib/python3.11/site-packages/pyVoIP/SIP.py", line 853, in recv_loop
    with acquired_lock_and_unblocked_socket(self.recvLock, self.s):
  File "/usr/lib/python3.11/contextlib.py", line 137, in __enter__
    return next(self.gen)
           ^^^^^^^^^^^^^^
  File "/home/gtorassa/pyVoIP/projects/qosroaming/.venv/lib/python3.11/site-packages/pyVoIP/util.py", line 20, in acquired_lock_and_unblocked_socket
    socket.setblocking(True)
OSError: [Errno 9] Bad file descriptor

I’m using the virtual environment launched by:

python3 -m venv .venv
source .venv/bin/activate

I’m using Debian GNU/Linux 12 with kernel Linux 6.1.0-18-amd64