static <A> void removeSetFromListQuickly(L<A> l, Set<A> set) {
  if (l(set) < 10) {
    ListIterator<TripleWeb> it = l.listIterator();
    while (it.hasNext())
      if (set.contains(it.next()))
        it.remove();
  } else {
    L<A> l2 = emptyListWithCapacity(l);
    for (A a : l)
      if (!set.contains(a))
        l2.add(a);
    copyList(l2, l);
  }
}