public override FingerTree <WeightedElement <T>, double> App2(List <WeightedElement <T> > ts, FingerTree <WeightedElement <T>, double> f) { return(_finger.App2(ts, f)); }
public override FingerTree <SizedElement <T>, int> App2(List <SizedElement <T> > ts, FingerTree <SizedElement <T>, int> f) => _finger.App2(ts, f);