code: public void unregister(final Object listener) {
  		for (Class clazz = listener.getClass(); clazz != null; clazz = clazz.getSuperclass()) {
  			this.handlersByEventType.removeAll(clazz);
  		}
  	}
docs: Unregisters the object from the event-handlers.
  
  @param listener The object to unregster.