This change modernizes the utils implementation, adding type hints and fixing up some various style and idiom issues. The most interesting part of this is that the `execute` method now has override defines to ensure that type checkers know what it's returning based on the various arguments. Due to the way that KGB and `deprecate_non_keyword_only_args` interact, some unit tests needed to be updated to fix their expectations for called-with checks. Testing Done: Ran unit tests.