Christmas lights knot

So yesterday I went out to pick up some lunch and left my Roomba (robot vacuum cleaner) on. I have Christmas lights in the house that I leave up all year round. Usually I block the Roomba from going near them.

When I came home two entire light strings were wrapped in the workings of the Roomba. Big mess!!! I untangled most of it but this knot is just too complicated to tackle. It will have to stay this way.