// returns list of func(O) -> Bool
static L ai_makeTesters(Web web, WebNode op) {
  new L testers;
  
  for (Pair<S, WebNode> p : web_forwardRelationsTextPlusNodes(op)) {
    if (eqic(p.a, "that is")) {
      S property = p.b.text();
      testers.add(ai_makeTester(web, web_text(op), property));
    }
    else fail("Unknown condition: " + p);
  }
  
  ret testers;
}