Handling data validation (drop-down menus)

[yulqen]

https://stackoverflow.com/questions/50917384/read-drop-down-values-from-excel-using-pandas

The above shows how the objects are set up to get at data validation objects.

Currently, if an existing cell as data validation on it, then writing to it will remove the validation (drop down menu). If we wish to retain it, we may have to rebuild the validation, if that is possible.

bcompiler interface should also warn the user if a value is being written into the cell that does not meet the current validation.

[yulqen]

Also: https://openpyxl.readthedocs.io/en/stable/validation.html