static <A, B extends Cl<A>> void forEachLevel2(Iterable<B> l, IVF1<A> f) {
  if (l != null) for (B b : l)
    forEach(b, f);
}

static <A, B extends Cl<A>> void lambdaMapLike forEachLevel2(IVF1<A> f, Iterable<B> l) {
  forEachLevel2(f, l);
}