trying to use coreData with pickerview

hello, i'm looking to use coreData in a pickerview in swift. Here is my code, i don't know why it doesn't work... thanks for your help

import UIKit
import CoreData

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    

    
    
    
    var context : NSManagedObjectContext?
    
    
    var itemListe : [NSManagedObject] = []
    

    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
    }
    
    override func viewDidAppear(_ animated: Bool) {
        lireItem()
    }
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        1
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        itemListe.count
    }

    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        
        itemListe[row].value(forKey: "nom") as? String
        
    }
    
    
    @IBOutlet weak var NomItemTextField: UITextField!
    
    @IBAction func effacerDernierItemAction(_ sender: Any) {
        
        let requete = NSFetchRequest<NSFetchRequestResult>(entityName: "Item")
        
        do {
            let result = try context!.fetch(requete) as? [NSManagedObject]
            let objc = result?.last
            context!.delete(objc!)
            do {
                try context!.save()
                print("enregistrement effacé")
           
            } catch {
                print("erreur 1")
            }
            
        } catch {
            print("erreur 2")
        }
    }
    
    
    @IBAction func lireItemAction(_ sender: Any) {
        
        lireItem()
    }
    
    
    func lireItem() {
    
    let requete : NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Item")
    
    do {
        
        itemListe = try context?.fetch(requete) as! [NSManagedObject]
        
        for r in itemListe {
            
            if let nom = r.value(forKey: "nom"){
                print(nom)
            }
        }
        
    }catch{
        print("La requête a échoué")
    }
}
    
    
    @IBAction func enregistrerItemAction(_ sender: Any) {
        
        let nouvelItem = NSEntityDescription.insertNewObject(forEntityName: "Item", into: context!)
        
        
        nouvelItem.setValue(NomItemTextField.text, forKey: "nom")
        
        
        do {
            
            try context?.save()
            print("nouvelle item sauvegardé")
            
        }catch{
            
            print("Enregistrement échoué")
        }
    }
}