如何在Swift 3中调用函数内部的函数

Question

我尝试在tapBlarButton(_ sender: UITapGestureRecognizer)函数中调用函数viewWillAppear，但我不知道该怎么做，这是我的代码：

@IBOutlet weak var buttonFunction: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tapBlarButton(_:)))

    buttonFunction.addGestureRecognizer(tapGesture)

}

func tapBlarButton(_ sender: UITapGestureRecognizer) {

    print("Hello! ")

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // Here I want to call the function

}