我已经创建了一个自定义类来应用不同的渐变，正如你所看到的。但是我的问题是，我不能用它来添加渐变到一个自定义单元格

import UIKit

extension UIView {
    // MARK: - Creamos funcion para poder aplicar degrado vertical 2 colores
    func aplicarFondoDegradado() {
        let colorArriba =  UIColor(red: 255/255, green: 4/255, blue: 14/255, alpha: 1.0).cgColor
        let colorAbajo = UIColor(red: 0/255, green: 0/255, blue: 0/255, alpha: 1.0).cgColor
        
        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [colorArriba, colorAbajo]
        gradientLayer.locations = [0.0, 1.0]
        gradientLayer.frame = self.bounds
                
        self.layer.insertSublayer(gradientLayer, at:0)
    }
    func aplicarDegradadoCultural() {
        let colorInicio =  UIColor(red: 0/255, green: 56/255, blue: 255/255, alpha: 1.0).cgColor
        let colorFin = UIColor(red: 125/255, green: 195/255, blue: 226/255, alpha: 1.0).cgColor
        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [colorInicio, colorFin]
        gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
        // Set end point.
        gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
        gradientLayer.frame = self.bounds
        
        self.layer.insertSublayer(gradientLayer, at:0)
    }
    func aplicarDegradadoDeportes() {
        let colorInicio =  UIColor(red: 0/255, green: 56/255, blue: 255/255, alpha: 1.0).cgColor
        let colorFin = UIColor(red: 125/255, green: 195/255, blue: 226/255, alpha: 1.0).cgColor
     let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [colorInicio, colorFin]
        gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
    
        gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
        gradientLayer.frame = self.bounds
        
        self.layer.insertSublayer(gradientLayer, at:0)
    }
}

它是有效的，但问题是当我试图把梯度应用到动态单元时，它没有显示出来。
这是我的tableview控制器代码，其中包括自定义单元格控制器：

import UIKit

class EventosCustomCellController: UITableViewCell {
    

    @IBOutlet weak var imEvento: UIImageView!
    
    @IBOutlet weak var txtNombreEvento: UILabel!
    
    @IBOutlet weak var txtFechaEvento: UILabel!
    
    @IBOutlet weak var txtEstadoEvento: UILabel!
}

class ListaEventosTableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.title = "Eventos"
        
        
    }

    // MARK: - Table view data source

    override func viewWillAppear(_ animated: Bool) {
        
        
    }
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return eventos.contarEventos()
    }

    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "prototipoCeldaEvento", for: indexPath) as! EventosCustomCellController
        
        let evento = eventos.buscarEventoPorID(id: indexPath.row)
        cell.layer.borderWidth = 1
        cell.layer.borderColor =  UIColor.black.cgColor
        cell.imageView?.layer.cornerRadius = 30
        
        cell.txtNombreEvento?.text = evento?.nombre
        cell.txtFechaEvento?.text = evento?.fecha
        cell.txtEstadoEvento?.text = evento?.tipo
        //THE PROBLEM IS HERE THE GRADIENT IS NOT SHOWN
        //THE PROBLEM IS HERE THE GRADIENT IS NOT SHOWN
        if evento?.tipo == "deportivo"{
            cell.aplicarDegradadoCultural()}
        else if evento?.tipo == "cultural"{
            cell.aplicarFondoDegradado()            }
        else{
            cell.aplicarDegradadoDeportes()}
        cell.layer.masksToBounds = true
           cell.layer.cornerRadius = 10
        
        cell.imEvento.loadFrom(URLAddress: (evento?.imagenes![0])!)
      
        cell.imEvento.layer.cornerRadius = 25
        cell.imEvento.clipsToBounds = true
        cell.imEvento.layer.borderWidth = 3
        cell.imEvento.layer.borderColor =  UIColor.white.cgColor
        return cell
    }
    

    
    // Override to support conditional editing of the table view.
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }
   
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let celdaPulsada = tableView.indexPathForSelectedRow?.row
        eventos.devolverCeldaPulsada (id: celdaPulsada!)
    }}