code: public static void assertElementIsNotDisplayed(By locator, WebDriver driver) {
  		try {
  			waitUntil(ExpectedConditions.visibilityOfElementLocated(locator), driver);
  			throw new AssertionError("[assert KO] element " + locator + " is displayed; expected: NOT displayed");
  		} catch(TimeoutException e) {
  			logger.info("[assert OK] element " + locator + " is NOT displayed as expected");
  		}
  	}
docs: Explicitly wait until the given element is visible.
  If it is, throw {@link AssertionError}; else, do nothing.
  
  @param locator
  @param driver
  
  @throws AssertionError if element is visible