Hi Guix,

On Guix System

   guix ecab53c
     repository URL: https://git.savannah.gnu.org/git/guix.git
     branch: master
     commit: ecab53c320b1584a08f811b17a92bd9a50a50ff3

it's impossible to install jupyter in a new profile because it tries to 
propagate two different versions of python-ipython, you should be able 
to reproduce with:

$ guix package -p /tmp/tmp-profile -i jupyter
The following package will be installed:
    jupyter 1.0.0

guix package: error: profile contains conflicting entries for python-ipython
guix package: error:   first entry: python-ipython@7.9.0 
/gnu/store/z0yarar134q6sziqncjdlfg2h2w5b2yh-python-ipython-7.9.0
guix package: error:    ... propagated from python-ipywidgets@7.5.1
guix package: error:    ... propagated from jupyter@1.0.0
guix package: error:   second entry: python-ipython@7.9.0 
/gnu/store/avmg5jd7kccchxadsd9c7zq0p3shlk3w-python-ipython-7.9.0
guix package: error:    ... propagated from python-qtconsole@4.4.3
guix package: error:    ... propagated from jupyter@1.0.0
hint: You cannot have two different versions or variants of `jupyter' in 
the same profile.


The conflict seems to be caused because:

- 
/gnu/store/avmg5jd7kccchxadsd9c7zq0p3shlk3w-python-ipython-7.9.0depends 
on python-prompt-toolkit@3.0.5

- 
/gnu/store/z0yarar134q6sziqncjdlfg2h2w5b2yh-python-ipython-7.9.0depends 
on python-prompt-toolkit@2.0.7


This change seems to be introduced with 
32ba87c14fd5e5b54d95211cd9a159d568ce7c67 , which updates 
python-prompt-toolkit to 3.0.5 and to prevent python-ipywidgets, 
python-jupyter-console and python-widgetsnbextension tests from crashing 
builds them with python-prompt-toolkit@2.0.7.


Giacomo