code: public void setCount(Integer count) {
          if (count == null)
              throw new RuntimeException("Cannot set count to null. Call removeCount() if you wanted to remove the bubble");
  
          if (countElem == null)
              createAndAttachCountElement();
          countElem.setInnerText(count.toString());
      }
docs: Set the count bubble value. If null this will throw a runtime
  exception. To remove a count bubble call removeCount()