docs: public static ExpectedCondition<Boolean> invisibilityOf(final WebElement element) {
      return new ExpectedCondition<Boolean>() {
  
        @Override
        public Boolean apply(WebDriver webDriver) {
          return isInvisible(element);
        }
  
        @Override
        public String toString() {
          return "invisibility of " + element;
        }
      };
    }