code: public List<SimpleOrderedMap<Object>> list() {
      List<SimpleOrderedMap<Object>> list = new ArrayList<>();
      for (Entry<String, String> entry : idToVersion.entrySet()) {
        SimpleOrderedMap<Object> item = new SimpleOrderedMap<>();
        item.add("id", entry.getKey());
        item.add("size", versionToItem.get(entry.getValue()).size);
        item.add("version", entry.getValue());
        item.add("expiration", expirationVersion.get(entry.getValue()));
        list.add(item);
      }
      return list;
    }
docs: List.
  
  @return the list