         }
     }
     
-    public var nk_parentViewController: UIViewController? {
+    @objc public var nk_parentViewController: UIViewController? {
         var parentResponder: UIResponder? = self
         while parentResponder != nil {
             parentResponder = parentResponder?.next

import RxCocoa

public extension UIView {
    public func nk_addTarget(_ target: Any, action: Selector, for event: UIControl.Event) {
        self.nk_addSubview(UIButton()) {
            $0.snp.makeConstraints({ (make) in
                make.edges.equalToSuperview()

}

public extension UIView {
    @objc public func nk_autoHideKeyboardWhenTapOutside() {
        self.rx_tap()
            .bindNext({[unowned self]_ in
                self.endEditing(true)})
            .addDisposableTo(self.nk_disposeBag)
    }
    
    @objc public var nk_firstSubviewResponse: UIView? {
        if self.isFirstResponder {
            return self
        }
