func webView(_ webView: WKWebView, didReceive challenge:
    URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        let user = "user"
        let password = "password"
        let credential = URLCredential(user: user, password: password, persistence: URLCredential.Persistence.forSession)
        completionHandler(URLSession.AuthChallengeDisposition.useCredential, credential)

    }