docs: public static Condition cssClass(final String cssClass) {
      return new Condition("css class") {
        @Override
        public boolean apply(Driver driver, WebElement element) {
          String classes = element.getAttribute("class");
          return classes != null && contains(classes.split(" "), cssClass);
        }
  
        @Override
        public String toString() {
          return name + " '" + cssClass + '\'';
        }
      };
    }