uniqueItemsVal :: UniqueItems -> Vector Value -> Maybe UniqueItemsInvalid
uniqueItemsVal (UniqueItems True) xs
   | allUniqueValues xs = Nothing
   | otherwise          = Just (UniqueItemsInvalid xs)
uniqueItemsVal :: UniqueItems -> Vector Value -> Maybe UniqueItemsInvalid
uniqueItemsVal (UniqueItems True) xs
   | allUniqueValues xs = Nothing
   | otherwise          = Just (UniqueItemsInvalid xs)
uniqueItemsVal (UniqueItems True) xs
   | allUniqueValues xs = Nothing
   | otherwise          = Just (UniqueItemsInvalid xs)