点击“电子邮件”按钮时无法识别选择器错误

Question

class ContactViewController: UIViewController, MFMailComposeViewControllerDelegate {

override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction func emailSenden(_ sender: Any) {

    if !MFMailComposeViewController.canSendMail() {
        print("Mail services are not available")
        return
    } else {
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = self
            mail.setToRecipients(["someone@example.com"])
            mail.setSubject("Message to you")
            mail.setMessageBody("Hallo,\n", isHTML: false)

            present(mail, animated: true, completion: nil)

            mail.dismiss(animated: true, completion: nil)
            }

    }
}

这是我的代码。问题是，每次我想在我的应用程序中运行它时，我都会收到此错误： ***由于未捕获的异常终止应用程序＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; - [My_App.ContactViewController电子邮件：]：无法识别的选择器发送到实例0x100b22430＆＃39;

你能帮帮我吗？