func checkPassword() {

        let alert = UIAlertController(title: "Password", message: "What is your password", preferredStyle: .alert)

        let authenticateAction = UIAlertAction(title: "Authenticate", style: .default) { (action) in

            guard let textfield = alert.textFields?.first,
                let password = textfield.text else {
                    return
            }

            if (password == "alice so cute") {

                self.infoLabel.text = "Password successful"
                self.performSegue(withIdentifier: "secret", sender: self)

            } else {

                self.infoLabel.text = "incorrect password"
            }

        }

        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)

        alert.addTextField(configurationHandler: nil)

        alert.addAction(cancelAction)
        alert.addAction(authenticateAction)

        present(alert,animated: true)
    }