To make use of this attribute It is necessary to inherit a category from Exclusive base class-initializer or use a static helper approach: This essentially provides us an item that can do what we would like, but how do we actually set it on our course? Effectively, properties use decorators; https://share.evernote.com/note/f404b8b9-8407-e9b8-74a2-7bb0637d59f3