Start being much stricter about requiring StaticTuples everywhere. I may go back and loosen this restriction, but getting the code base StaticTuple pure is probably a good idea. The main reason to be 'looser' is so that things don't fail 'in the wild' just because someone calls an api with a tuple rather than a StaticTuple. However, I'd like the internals to be 'pure' if possible. We'll see.