Adding UILabel programatically in Swift 3

Label.swift

class ViewController: UIViewController {

    var label : UILabel! = nil
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.label = UILabel(frame: CGRect(x: 0, y: 0, width: 300, height: 21))
        self.label.font = UIFont.preferredFont(forTextStyle: .footnote)
        self.label.textColor = .black
        self.label.center = CGPoint(x: 200, y: 300)
        self.label.textAlignment = .center
        self.label.text = "Demo Text UILabel"
        self.logOutButton.isHidden = true
      }
    }