Package: python3-jupyter-client Version: 6.1.11-2 When running a jupyter notebook that spawns processes, in my case using multiprocessing.Pool.starmap(), then occasionally the notebook kernel is hit by an exception complaining about "Duplicate Signature" in zmqstreams.
The bug is known upstream and there is a commit by 2021-06-07 on master: https://github.com/jupyter/jupyter_client/pull/655/commits/9ac65f998ec1398a4dd206d8d18f3babf9947d7e The patch is a one-line change which I manually applied on my system here, after which the errors disappeared. Although the errors occur infrequently and are hard to trigger, I have a notebook that spawns many processes and before applying the patch I could not run the notebook through without restarting the kernel, say, three to four times.
