cmprsk python package example notebook doesn't work

I'm using Python 3.11.1. I've installed https://github.com/OmriTreidel/cmprsk (1.0.0, the latest version) on a new virtual environment, I've installed rpy2 3.4.5 like the documentation suggested, I'm using R 4.2.2 and I've installed the cmprsk package as suggested.

When I run the example notebook provided in the GitHub, I have ValueError: setting an array element with a sequence. The requested array has an inhomogeneous shape after 1 dimensions. The detected shape was (6,) + inhomogeneous part.

from cmprsk python package example notebook doesn't work