Could we add some kind of Slug translation?

I'd like to use this library but besides just selecting a State with the VA / Virginia I'd like to have a slug version for using in URLs so just "va". I'm trying to figure out how to best do this maybe lowering "VA" to "va". I see there is some data structures for the normalization but I was a little confused. As far as what I would envision for the normalization of the USStateField it would be what I said above just the lower case version of the 2 letter abbreviation. Not what I saw like "virginia" for VA and say "nj" for New Jersey.

Thanks for any comments and your thoughtful understanding. If you have a suggestion for how to just best do it with your library myself I'm open to ideas.