when I add an edit data in the Core data then add another nil cell on the Table

before write down what I want to say
my English is not good but plz give me an answer
my situation is when I edit my text and save it it works well but the nil cell is added on the table at the same time
when I add a new text then it never make a nil cell but only edit works wrong plz give me any advices or answer

here is my code

import UIKit

import CoreData

class ComposeViewController: UIViewController {



    

    

    

    let formatter:DateFormatter = {

       let formatter = DateFormatter()

        formatter.dateFormat = "YYYY년 MM월 dd일 E요일"

        formatter.locale = Locale.init(identifier: "koKR")

       return formatter

    }()



   

//    var segueData: TodoList?

    var editSegueData: TodoList?

    var itemContent:[NSManagedObject] = []

    

    @IBOutlet weak var dateLabel: UILabel!

    @IBOutlet weak var textView: UITextView!

    

    @IBAction func save( sender: AnyObject) {

        guard let memo = textView.text , memo.count > 0 else{

            alert(message: "텍스트를 입력하세요")

            return

        }

        

        let date = Date()

        let appDelegate = UIApplication.shared.delegate as! AppDelegate

        let context = appDelegate.persistentContainer.viewContext

        let entity = NSEntityDescription.entity(forEntityName: "TodoList", in: context)!

        let theTitle = NSManagedObject(entity: entity, insertInto: context)

        let checkBoxBool = false



        

        if let target = editSegueData

        {

            print("target.content = \(target.content) \(target.insertDate)")

            target.content = memo

            do

            {

                try context.save()

                

//                itemContent.append(theTitle)

            }

            catch

            {

                print("There was a error in saving")

            }

            NotificationCenter.default.post(name:ComposeViewController.memoDidChange, object: nil)

        }

        else

        {

            theTitle.setValue(memo, forKey: "content")

            theTitle.setValue(date, forKey: "insertDate")

            theTitle.setValue(checkBoxBool, forKey: "checkBox")

            do

            {

                try context.save()

//                itemContent.append(theTitle)

            }

            catch

            {

                print("There was a error in saving")

            }

        }

        NotificationCenter.default.post(name: ComposeViewController.newMemoDidInsert, object: nil)

        



        dismiss(animated: true, completion: nil)

    }

    

    @IBAction func cancelButton(_ sender: Any) {

        dismiss(animated: true, completion: nil)

    }

    

    

    override func viewDidLoad() {

        super.viewDidLoad()

        dateLabel.text = formatter.string(from: Date())

        if let memo = editSegueData {

            navigationItem.title = "EDIT"

            textView.text = memo.content

        }else{

            navigationItem.title = "NEW"

            textView.text = ""

        }



        // Do any additional setup after loading the view.

    }

    



    /*

    // MARK: - Navigation



    // In a storyboard-based application, you will often want to do a little preparation before navigation

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        // Get the new view controller using segue.destination.

        // Pass the selected object to the new view controller.

    }

    */



}



extension ComposeViewController {

    static let newMemoDidInsert = Notification.Name("newMemoDidInsert")

    static let memoDidChange = Notification.Name(rawValue: "memoDidChange")

}