I think that TestUser should have a list with `windows_extra_rigth` . This is a list of rights which will be granted after account is creteated... and only OSWindows.addUser will care about these attribute of TestUser...


is the same time, os_administation.deleteUser(user) could check that list and remove those permissions in a transparent way.

In this way you will not have to make addRight and removeRight a public api for os_administration.