docs: private Element findFirstElementByTagName(String tag, Node node) {
          if (node.nodeName().equals(tag))
              return (Element) node;
          else {
              int size = node.childNodeSize();
              for (int i = 0; i < size; i++) {
                  Element found = findFirstElementByTagName(tag, node.childNode(i));
                  if (found != null)
                      return found;
              }
          }
          return null;
      }