This looks like a great and very polished project! Leveraging python in soeadsheets is a great idea - probably why excel are doing it already, but it's nice to see an implantation that's so clear and easy to use.

It's hardly a criticism of pysheets specifically, but I wish spreadsheets were more restrictive (I.e. force sheets into a table format) so that people could build out spreadsheets in an org without creating an unholy mess that needs to be picked apart and reversed engineered in something that isn't a spreadsheet.