openpyxl has pretty good docs prepared using sphinx, though they can be hard to navigate.
Using Dash makes that easier for me, so here's how to create a Dash docset for openpyxl, using the doc2dash tool; by default this will install it directly into Dash, but see doc2dash
's documentation for more options.
mkdir openpyxl__for_dash_docset
cd openpyxl__for_dash_docset
hg clone https://foss.heptapod.net/openpyxl/openpyxl
cd openpyxl
hg up 3.0.8 # Or whatever
python3 -m venv .venv && source .venv/bin/activate
pip install -U -r requirements.txt
pip install -e .
tox -e doc
pip install doc2dash
doc2dash -A -f -j -n openpyxl -I index.html -u https://openpyxl.readthedocs.io/en/stable .tox/doc/tmp/html