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