type-hinting numpy mixed array records

[aryarm]

There are at least two times where I've wanted to be able to place restrictions on the type of numpy mixed array records that my functions can accept:

1. When storing values in the AssocResults class
2. When storing values in the Variant class

Specifically, I want to require that the numpy mixed array record that is received has specific attributes. What's the best way for me to do that?

One idea is to write a class that extends numpy's and then calls a checker in the init.