static Pair<WebNode> web_findTriple(Web web, S a, S rel, S b) {
  for (Pair<WebNode> p : web_relations(web)) {
    //print(p.a.text() + " / " + a);
    //print(p.b.text() + " / " + b);
    if (web_hasLabel(p.a, a) && web_hasLabel(p.b, b) && web_hasLabelIC(p, rel))
      ret p;
  }
  null;
}