svoid test_restructure_MRUCache() {
  new MRUCache o;
  o.maxSize = 5;
  o.put("a", true);
  print(structure(o));
  O o2 = restructure(o);
  assertTrueVerbose(o2 instanceof MRUCache);
  assertEqualsVerbose(ll(pair("a", true)), mapToPairs(o2));
  assertEqualsVerbose(5, o2.maxSize);
}