@TODO Oct 17th, 2020 - Ben Culkin - :ExceptionOverview
	Go over all of the code and make sure that the exceptions we are throwing
	are of the right type, and have a useful message. In some contexts, this may
	mean creating some wrapper exception types, just to make it clear what
	exactly has gone wrong

@TODO September 17th, 2022 - Ben Culkin - :Triether
	Implement some sort of Either for three types; because that is occasionally useful,
	and more convenient than Either<Either<X, Y>, Z> and the like