public static <T> PersistentTreeSet<T> ofComp(Comparator<? super T> comp) {
        return new PersistentTreeSet<>(PersistentTreeMap.empty(comp));
    }
public static <T> PersistentTreeSet<T> ofComp(Comparator<? super T> comp) {
        return new PersistentTreeSet<>(PersistentTreeMap.empty(comp));
    }
public static < T > PersistentTreeSet < T > ofComp ( Comparator < ? super T > comp ) { return new PersistentTreeSet <> ( PersistentTreeMap . empty ( comp ) ) ; }
Returns a new PersistentTreeSet of the given comparator.  Always use this instead of starting
with empty() because there is no way to assign a comparator to an existing set.
Returns a new PersistentTreeSet of the given comparator . Always use this instead of starting with empty () because there is no way to assign a comparator to an existing set .