static Iterable<ReferenceID> withAllSubclassesIfSealed(Utils utils, ReferenceID sealedClassId) {
    Iterators.Function<ReferenceID, Iterable<? extends ReferenceID>> withSubclassesIfSealed =
      id -> flat(map(utils.getNodes(id, JvmClass.class), n -> isSealed(n)? utils.directSubclasses(n.getReferenceID()) : Collections.emptyList()));
    return recurse(sealedClassId, withSubclassesIfSealed, true);
  }
static Iterable<ReferenceID> withAllSubclassesIfSealed(Utils utils, ReferenceID sealedClassId)