static void web_addWebToWeb(Web web, Web w) {
  new HashMap<WebNode, WebNode> map;
  for (WebNode node : web.nodes) {
    WebNode n = w.newNode();
    n.addLabels(node.labels);
    map.put(node, n);
  }
  for (Pair<WebNode> p : keys(web.relations))
    w.relations.put(pair(assertNotNull(map.get(p.a)), assertNotNull(map.get(p.b))), assertNotNull(map.get(web.getRelation(p))));
}