Radio Button Swift

@IBOutlet weak var radioButBoth: UIButton! {
        didSet {
            radioButBoth.setImage(UIImage(named:"unchecked"), for: .normal)
            radioButBoth.setImage(UIImage(named:"checked"), for: .selected)
        }
    }

    @IBAction func radioButMethod(_ sender: UIButton) {
        radioButBoth.isSelected = false
        radioButOnline.isSelected = false
        radioButOffline.isSelected = false
        if sender == radioButOnline {
            debugPrint("radioButOnline")
            radioButOnline.checkboxAnimation {

            }
        } else if sender == radioButOffline {
            debugPrint("radioButOffline")
            radioButOffline.checkboxAnimation {

            }
        } else if sender == radioButBoth {
            debugPrint("radioButBoth")
            radioButBoth.checkboxAnimation {

            }
        }
    }

extension UIButton {
    //MARK:- Animate check mark
    func checkboxAnimation(closure: @escaping () -> Void){
        guard let image = self.imageView else {return}

        UIView.animate(withDuration: 0.1, delay: 0.1, options: .curveLinear, animations: {
            image.transform = CGAffineTransform(scaleX: 0.85, y: 0.85)

        }) { (success) in
            UIView.animate(withDuration: 0.1, delay: 0, options: .curveLinear, animations: {
                self.isSelected = !self.isSelected
                //to-do
                closure()
                image.transform = .identity
            }, completion: nil)
        }
    }
}

    @discardableResult
    private func checked(index: Int? = nil) -> Int {

        if index != nil {
            if index == 1 {
                radioButOnline.isSelected = true
            } else if index == 2 {
                radioButOffline.isSelected = true
            } else {
                radioButBoth.isSelected = true
            }
        } else {
            if radioButOnline.isSelected {
                return 1
            } else if radioButOffline.isSelected {
                return 2
            } else if radioButBoth.isSelected {
                return 3
            }
        }
        return 0
    }

let tuitionType:Int = checked()

self.checked(index: self.tutorDetail.tuition_type)