RE: multiple inheritance
> Clearly "country" is not a primitive concept, though it is an important one.
It is critical to distinguish between importance and primitiveness. We have
found a lot of difficulty in developing models where people wanted to see
the things that were important to them, rather than what was
'primitive' is relative to the required purpose of your model, and is thus
a representational artifact of how much detail is required in your model.
Sometimes country woudl be a perfectly suitable primitive, in other cases,
it woudl have to be broken down into finer grain primitives.