ArbitraryVariable
data class ArbitraryVariable(val default: Serializable, values: List<Serializable?>) : AbstractPrintableVariable<Serializable?> (source)
A variable that can take any value from an arbitrary, finite set.
This implementation stores values in an immutable ordered set. Values and the default are non-nullable: an ArbitraryVariable always contains at least a default value and a (possibly empty) set of candidate values.