code: @Override
    public void add(T indexElement) {
      mapByNum.put(indexElement.getNumber(), indexElement);
      if (mapByRawNum != null) {
        mapByRawNum.put(indexElement.getRawNumber(), indexElement);
      }
      if (mapById != null) {
        mapById.put(indexElement.getId(), indexElement);
      }
    }
docs: Add a {@link umich.ms.datatypes.index.IndexElement} to the index. Don't use this method, unless
  you're building a new index.
  
  @param indexElement scan index element implementation