Add Unit Tests for .demask Method
Add Unit Tests for .demask Method

Add unit tests for the .demask method, which will replace the unmasked
attribute of the MaskableAttribute object with the masked value,
resulting in a permanent loss of the unmasked value (desirable for when
the aliases with the masked attribute are no longer needed).

billy-ran-away/maskable_attribute,billy-ran-away/maskable_attribute