public Either<TRes1, TRes2> Map<TRes1, TRes2>(
	Func<TA, TRes1> map1,
	Func<TB, TRes2> map2
)

member Map : 
        map1 : Func<'TA, 'TRes1> * 
        map2 : Func<'TB, 'TRes2> -> Either<'TRes1, 'TRes2>