** A simple implementation of `NotFoundErr`.** This class can not extend 'ArgErr' due to [Cannot extend sys Errs in Javascript]`http://fantom.org/forum/topic/2468`.@Js constclass ArgNotFoundErr : Err, NotFoundErr {overrideconst Str?[] availableValuesnew make(Str msg, Obj?[] availableValues, Err? cause := null) : super.make(msg, cause){this.availableValues = availableValues.map {it?.toStr }.sort}override Str toStr(){ NotFoundErr.super.toStr }}