Documentation empty for model_repository, reports, report_images

The API documentation for the model_repository, reports & report_images services seems to be missing:
https://sassoftware.github.io/python-sasctl/api/services/model_repository.html
https://sassoftware.github.io/python-sasctl/api/services/report_images.html
https://sassoftware.github.io/python-sasctl/api/services/reports.html

In the case of the model_repository service, the docstring on line 7 in services/model_repository.py is still read but not the rest of the code.

I tried cloning this repo to build the documentation using: tox -e py38-doc but sphinx returned the error:
Extension error:
Could not import extension numpydoc (exception: No module named 'numpydoc')
Changing from numpydoc to napoleon then returned:
Theme error:
no theme named 'pydata_sphinx_theme' found (missing theme.conf?)

Even installing both of the above packages with pip install failed to resolve these sphinx errors.

In addition to understanding why the docs are missing it would be good to get assistance in resolving the above sphinx errors,

Thank you!