UICollectionView + NSFetchedResultsController Swift 3 / iOS 10

UICollectionView + NSFetchedResultsController.swift

    var blockOperations: [BlockOperation] = []
    
    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
    
        if type == NSFetchedResultsChangeType.insert {
            print("Insert Object: \(newIndexPath)")
            
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.insertItems(at: [newIndexPath!])
                    }
                    })
            )
        }
        else if type == NSFetchedResultsChangeType.update {
            print("Update Object: \(indexPath)")
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.reloadItems(at: [indexPath!])
                    }
                    })
            )
        }
        else if type == NSFetchedResultsChangeType.move {
            print("Move Object: \(indexPath)")
            
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.moveItem(at: indexPath!, to: newIndexPath!)
                    }
                    })
            )
        }
        else if type == NSFetchedResultsChangeType.delete {
            print("Delete Object: \(indexPath)")
            
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.deleteItems(at: [indexPath!])
                    }
                    })
            )
        }
    }
    
    public func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange sectionInfo: NSFetchedResultsSectionInfo, atSectionIndex sectionIndex: Int, for type: NSFetchedResultsChangeType) {
        
    
        if type == NSFetchedResultsChangeType.insert {
            print("Insert Section: \(sectionIndex)")
            
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.insertSections(NSIndexSet(index: sectionIndex) as IndexSet)
                    }
                    })
            )
        }
        else if type == NSFetchedResultsChangeType.update {
            print("Update Section: \(sectionIndex)")
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.reloadSections(NSIndexSet(index: sectionIndex) as IndexSet)
                    }
                })
            )
        }
        else if type == NSFetchedResultsChangeType.delete {
            print("Delete Section: \(sectionIndex)")
            
            blockOperations.append(
                BlockOperation(block: { [weak self] in
                    if let this = self {
                        this.collectionView!.deleteSections(NSIndexSet(index: sectionIndex) as IndexSet)
                    }
                    })
            )
        }
    }
    
    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        collectionView!.performBatchUpdates({ () -> Void in
            for operation: BlockOperation in self.blockOperations {
                operation.start()
            }
            }, completion: { (finished) -> Void in
                self.blockOperations.removeAll(keepingCapacity: false)
        })
    }
    
    deinit {
        for operation: BlockOperation in blockOperations {
            operation.cancel()
        }
        
        blockOperations.removeAll(keepingCapacity: false)
    }
    

Getting this error Thread 1: "attempt to delete item 1 from section 0 which only contains 1 items before the update". Don't know what to do, pls help.