This is my `NSBatchUpdateRequest`:

```
    let batchUpdateRequest = NSBatchUpdateRequest(entityName: "WLItem")
    batchUpdateRequest.predicate = NSPredicate(format: "source != rt")
    batchUpdateRequest.propertiesToUpdate = ["position": 2]
    batchUpdateRequest.resultType = NSBatchUpdateRequestResultType.UpdatedObjectsCountResultType

    do {
        let batchUpdateResult = try NSManagedObjectContext.MR_defaultContext().executeRequest(batchUpdateRequest) as! NSBatchUpdateResult
    } catch {
        print("error: \(error)")
    }

```

output on console is:

> 
> error: NilError
> 
> 
> 

What is wrong? Is it a problem with XCode7? I am working with `NSBatchUpdateRequest` first time, so I do not know whether was it like that before or not. For me that code should just works.