This is a slightly modified copy of the same module from `contrib` package.
record Quantity : TypeShow Quantity.min : Quantity -> Natmin : Quantity -> Nat.max : Quantity -> Maybe Natmax : Quantity -> Maybe Natbetween : Nat -> Nat -> QuantityatLeast : Nat -> QuantityatMost : Nat -> Quantityexactly : Nat -> QuantityinOrder : Quantity -> Bool