Allow user to specify a Worksheet factory
Created originally on Bitbucket by simsong (Simson Garfinkel)
Currently it is hard-coded here that Workbook creates new Worksheets by calling the Worksheet() constructor directly. It would be useful if the constructor was a property so that the user could change it. This would allow the user to have their own Worksheet subclass and for it to be natively used.
I would like this functionality, so I plan to implement this and send it as a pull request. This issue is a placeholder for that.