Programatically extracting cells with student answers

[joelostblom]

Is your feature request related to a problem? Please describe.
I'm trying to extract students' answers programatically from the notebooks to do some simple plagiarism checking. I can see that in the instructor version the solution cells are tagged with otter-assign-solution but I don't see these same tags in the student notebooks, so I am struggling to extract both code and manually graded question in a consistent manner without manual intervention.

Describe the solution you'd like
A consistent tag that indentifies all cells that student have entered answers in

Describe alternatives you've considered
There might very well be alternative working approach to this that I'm not aware of, happy to be enlightened if this is already possible.

Additional context
Somewhat related to #622

[chrispyles]

I can add a tag like you suggest but note that if students delete/add new cells, the new cells won't be identified.

[joelostblom]

Thanks @chrispyles, I think adding the tag would still be helpful for the majority of cases since it is rare in my experience that students delete cells. Maybe it is also possible to set cells to not be deletable even if they are still editable?