Swift和CoreData，关系问题(NSSet) - [NSSet intersectsSet:]: set参数不是NSSet

I've been trying to get my head around adding objects in relationships using CoreData and Swift. I am at a loss, I do not understand why my code does not work. I am trying to add an "Event" to a "Team". I can not find the difference between accepted answers (that should work), and my code (that does not).I've been trying to get my head around adding o