 //        assert(changes != nil, "Invalid changes")    
         let moc = BreezeStore.contextForType(.Background)
         moc.performBlock { () -> Void in
-            changes!(.Background)
+            changes(.Background)
 
             var error: NSError?
             moc.save(&error)

//        assert(changes != nil, "Invalid changes")
        let moc = BreezeStore.contextForType(.Main)
        moc.performBlock {
            changes!(.Main)

            var error: NSError?
            moc.save(&error)

//        assert(changes != nil, "Invalid changes")
        let moc = BreezeStore.contextForType(.Main)
        moc.performBlockAndWait { () -> Void in
            changes(.Main)

            var error: NSError?
            moc.save(&error)
