code: public static Elements select(String query, Element root) {
          Validate.notEmpty(query);
          return select(QueryParser.parse(query), root);
      }
docs: Find elements matching selector.
  
  @param query CSS selector
  @param root  root element to descend into
  @return matching elements, empty if none
  @throws Selector.SelectorParseException (unchecked) on an invalid CSS query.