After installing python-jupyter_client, there is an error when trying to run jupyter kernelspec:
polomi@solus ~ $ jupyter kernelspec Traceback (most recent call last): File "/usr/bin/jupyter-kernelspec", line 6, in <module> from pkg_resources import load_entry_point ImportError: No module named pkg_resources
This is solved by installing python-setuptools. So should it possibly be added as a rundep?
Also jupyter-kernelspec is provided by jupter_client, not jupyter_core (see the documentation), so that's where I suggest to add the dependency.