code: public Node item(int index) {
          try {
              return item(index, null);
          } catch (ParserConfigurationException e) {
              throw new RuntimeException(e);
          }
      }
docs: Returns the indexth item in the map. If index is greater than or equal to
  the number of nodes in this map, this returns null; if the item returned
  is a namespace declaration, it is represented as an attribute whose owner
  document is a document containing the attribute only.