My Menu Bar Extra Item does not display. Why?

Hello:

I am creating a Menu Bar Extra Item for my MAC os App. I have the following code but nothing displays on the menu bar. W ould appreciate some advice on where in the code I need to make changes:

import Cocoa

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
   
//@IBOutlet weak var window: NSWindow!
let statusItem = NSStatusBar.system.statusItem(withLength:NSStatusItem.squareLength)
//   var item: NSStatusItem? = nil
    @objc func QuitScorCentMasterReview(_ sender: Any?) {
          NSApplication.shared.terminate(self)
        }
    func applicationDidFinishLaunching(_ aNotification: Notification) {
       
        if let button = statusItem.button {
          button.image = NSImage(named:NSImage.Name("SMR_icon.png"))
          button.action = #selector(QuitScorCentMasterReview(_:))
        }
       
        func constructMenu() {
          let menu = NSMenu()

    
          menu.addItem(NSMenuItem(title: "End the Application", action: #selector(NSApplication.terminate(_:)), keyEquivalent: ""))

            statusItem.menu = menu
        }
       
        constructMenu()
       
    }