View Controller doesn't find a func member - swift

Question

I'm getting this error:
Value of type 'DiscountVC' has no member 'calculateTotal'. And I have no clue why. Basically, I'm trying to make this calculator:
It should work as soon as you insert any value on the discountTF. Also, I have some pre-discounted buttons that just edit the discount value. The subtotalLabel value comes from another ViewController. For testing purposes, I'm using an initial value of 999.9.
import UIKit
class DiscountVC: UIViewController {
#IBOutlet var numericKeyboardView: UIView!
#IBOutlet var subtotalLabel: UILabel!
#IBOutlet var discountTF: UITextField!
#IBOutlet var totalLabel: UILabel!
var subtotal : Double = 999.9
var discount : Double = 0.0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
addKeyboard(view: numericKeyboardView)
subtotal = 999.9
discount = 0.0
discountTF.addTarget(self, action: #selector(self.calculateTotal(_:)), for: UIControl.Event.editingChanged)
}
override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent
}
func calculateTotal() {
let totalDouble = Double(subtotal) - Double(discountTF.text!)!
totalLabel.text = String(totalDouble)
}
func addKeyboard(view: UIView) {
let numericKeyboard = KeyboardVC(nibName: "NumericKeyboardVC", bundle: nil)
view.addSubview(numericKeyboard.view)
addChild(numericKeyboard)
}
#IBAction func fivePercentedButtonPressed(_ sender: Any) {
discount = Double(discountTF.text!)! * 0.05
discountTF.text = "\(discount)"
print(discount)
}
#IBAction func tenPercentButtonPressed(_ sender: Any) {
discount = Double(discountTF.text!)! * 0.1
discountTF.text = "\(discount)"
print(discount)
}
#IBAction func fifteenPercentButtonPressed(_ sender: Any) {
discount = Double(discountTF.text!)! * 0.15
discountTF.text = "\(discount)"
print(discount)
}
#IBAction func twentyPercentButtonPressed(_ sender: Any) {
discount = Double(discountTF.text!)! * 0.2
discountTF.text = "\(discount)"
print(discount)
}
#IBAction func goButton(_ sender: Any) {
}
}

Answer 1

Change to
#objc func calculateTotal(_ tex:UITextField){ --- }