@Gevater_Tod4711,
(1) 'getOneIntersectingObject' is an Actor class method
(2) 'getOneIntersectingObject' returns an Object (not a list)
Because of (1) above, you cannot use the method on a World object ('getWorld' returns a World object)
Because of (2) above, you cannot use 'isEmpty()' on what it returns ('isEmpty' is a List class method)
It should be