In WKWebView how do I make it so it fits the margins set within storyboard?

Question

For the webkit I'm having problems setting its size of it. I'm using Swift with Storyboard and I've tried some other solutions but none have worked here:

class ViewController: UIViewController, UIGestureRecognizerDelegate, UIWebViewDelegate, WKNavigationDelegate  {
    
    let url = URL(string: "google.com")!
    var webView: WKWebView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        webView = WKWebView(frame: CGRect( x: 0, y: 20, width: self.view.frame.width, height: self.view.frame.height - 20 ), configuration: WKWebViewConfiguration() )
        self.view.addSubview(webView)
        webView.load(URLRequest(url: url))
        self.webView.allowsBackForwardNavigationGestures = true
    }
}