[DanielBMarkham]

I hate these discussions because you're right, but in a limited way.

Yes, it is impossible. I should have said something like "locally centralized to the compilation unit"

As gandalf pointed out, "IsValid" really asks a bunch of questions at the same time, and talking about it in the abstract is always going to miss the full depth. As a for-instance, there's clean data in terms of my datastore and then there's clean data in terms of whatever app I'm looking at. In a system of any size, these are most likely not the same thing. (And yes, that drives us crazy, but such is the way of large datastores)