docs: public static String getCascadeValue(final Element elem, final String attrName) {
          Element current = elem;
          while (current != null) {
              final Attr attr = current.getAttributeNode(attrName);
              if (attr != null) {
                  return attr.getValue();
              }
              final Node parent = current.getParentNode();
              if (parent != null && parent.getNodeType() == Node.ELEMENT_NODE) {
                  current = (Element) parent;
              } else {
                  break;
              }
          }
          return null;
      }