Possible typo in Voila doc example on ipywidgets import

[edwenger]

Really minor thing I came across trying to build upon the Voila example code from the docs: https://github.com/InstituteforDiseaseModeling/covasim/blob/9e94ccda7616fba4faf9b010f8cb3952fff7f051/docs/tutorials/tut_deployment.ipynb#L81

I get an error that ipywidgetsets can't be imported, but if I switch that to just ipywidgets, it works fine.

Not sure if that's a system environment difference or a typo, but thought I'd flag in case you know.

Thanks.

[cliffckerr]

Thanks @edwenger ! Agree this looks like a typo.

[cliffckerr]

Fixed