Units
Base class for all types that can represent a unit of measure. A Units type can have multiple "members", each being some fraction of the base unit for that type. Time for example, might have seconds as the base unit and minute as a unit that is 60 times the base unit. This allows for a set of different representations of the unit.
Parameters
suffix
to use when printing the unit in a human-readable way
ratio
of this unit relative to the base-unit