     public var onObjectsChanged: (([NSManagedObject]) -> ())?
     
     func handleObjectsChanged(notification: NSNotification) {
+        guard let request = self.request else { return }
+        
         let changedObjects = CDObserver.changedObjects(forNotification: notification, includeChanges: self.includeChanges)
         var changedEntities = Set<String>()
         

    }
    
    public func fetch() {
        do {
            let results = try context.fetch(request) as! [NSManagedObject]
            self.results = results

        case none
    }
    
    public init(context: NSManagedObjectContext, request: NSFetchRequest<NSFetchRequestResult>?, includeChanges: Columns = .all, callback: CDCallback? = nil) {
        self.context = context
        self.request = request
        self.callback = callback
