override func viewDidLoad() {
    super.viewDidLoad()
    let checkbox: GDCheckbox = GDCheckbox()
    // Background color of the box
    checkbox.baseColor = UIColor.white
    // In case of check box, determine the animation duration of the check mark
    checkbox.animationDuration = 1.0
    // Determine if check mark should fill with animation
    checkbox.shouldAnimate = false
    // Color of the check mark / fill area -- no matter if isCurcular is on or off
    checkbox.checkColor = UIColor.red
    // Width of the check mark / fill area -- no matter if isCurcular is on or off
    checkbox.checkWidth = 3.0
    // Color of container border. If shouldFillContainer is set to true, container background also will be override with this color when CheckBox / Radio Button is selected.
    checkbox.containerColor = UIColor.blue
    // Determine if container should be filled when selected
    // Note: if set to true, it will override `baseColor` when control is selected
    checkbox.shouldFillContainer = false
    // Border width of container view
    checkbox.containerWidth = 5.0
    // Determine if it's a check box or a radio button
    checkbox.isRadioButton = false
    
    // Determine container shpae type for selected state
    // For CheckBox -> Check mark when true or square when false
    // For RadioButton -> Check mark when true or circle when false
    checkbox.showCheckMark = false
    // Set default state of the control
    checkbox.isOn = false
    
    self.view.addSubview(checkbox)
}
@IBAction func onCheckBoxPress(_ sender: GDCheckbox) {
    let state = sender.isOn ? "ON" : "OFF"
    // Trigger action
}