docs: protected void fireAttributeClearedEvent() {
  		if (this.listeners != null && isEventFirable()) {
  			final AttributeChangeEvent event = new AttributeChangeEvent(
  					//source
  					this,
  					//type
  					Type.REMOVE_ALL,
  					//old name
  					null,
  					//old value
  					null,
  					//current name
  					null,
  					//current value
  					null);
  			for (final AttributeChangeListener listener : this.listeners) {
  				listener.onAttributeChangeEvent(event);
  			}
  		}
  	}