docs: public static List<Element> getElementsByClass(String className, Tag tag, Element rootElement) {
  
          if ((rootElement == null) || (className == null) || (className.trim().length() == 0) || (tag == null)) {
              return null;
          }
          className = className.trim();
          List<Element> result = new ArrayList<Element>();
          if (internalHasClass(className, rootElement)) {
              result.add(rootElement);
          }
          NodeList<Element> elements = querySelectorAll(tag + "." + className, rootElement);
          for (int i = 0; i < elements.getLength(); i++) {
              result.add(elements.getItem(i));
          }
          return result;
      }