Building documentation requires Fenics about matscipy HOT 4 CLOSED

WARNING: [autosummary] failed to import matscipy.electrochemistry.poisson_nernst_planck_solver_fenics.
Possible hints:
* ModuleNotFoundError: No module named 'fenics'
* AttributeError: module 'matscipy.electrochemistry' has no attribute 'poisson_nernst_planck_solver_fenics'
* ImportError: 

building [html]: targets for 30 source files that are out of date
updating environment: [new config] 102 added, 0 changed, 0 removed
/home/jotelha/git/matscipy/docs/applications/cylinder_configurations.ipynb: Executing notebook using local CWD [mystnb]                                                                                           
/home/jotelha/git/matscipy/docs/applications/cylinder_configurations.ipynb: Executed notebook in 10.51 seconds [mystnb]
/home/jotelha/git/matscipy/docs/applications/elastic_constants.ipynb: Executing notebook using local CWD [mystnb]                                                                                                 
/home/jotelha/git/matscipy/docs/applications/elastic_constants.ipynb: Executed notebook in 21.82 seconds [mystnb]
/home/jotelha/git/matscipy/docs/applications/electrochemistry_1.py: Executing notebook using local CWD [mystnb]                                                                                                   
/home/jotelha/git/matscipy/docs/applications/electrochemistry_1.py: Executed notebook in 35.99 seconds [mystnb]
/home/jotelha/git/matscipy/docs/applications/electrochemistry_2.py: Executing notebook using local CWD [mystnb]                                                                                                   
/home/jotelha/git/matscipy/docs/applications/electrochemistry_1.py:440002: WARNING: Non-consecutive header level increase; H1 to H3 [myst.header]
/home/jotelha/git/matscipy/docs/applications/electrochemistry_1.py:510002: WARNING: Non-consecutive header level increase; H1 to H3 [myst.header]
/home/jotelha/git/matscipy/docs/applications/electrochemistry_1.py:570002: WARNING: Non-consecutive header level increase; H1 to H3 [myst.header]

Exception occurred:
  File "/home/jotelha/git/matscipy/isolated-venv/lib/python3.8/site-packages/myst_nb/core/execute/direct.py", line 50, in start_client
    raise ExecutionError(str(self.path)) from result.err
myst_nb.core.execute.base.ExecutionError: /home/jotelha/git/matscipy/docs/applications/electrochemistry_2.py
The full traceback has been saved in /tmp/sphinx-err-6yytmx4r.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
make: *** [Makefile:55: html] Error 2