   
   public static func start() {
     guard !pretendUberIsInstalled else { return }
+    guard let clientId = self.clientId else { return }
     
     let urlScheme = TKConfig.shared.appURLScheme()
     let appName = Bundle.main.productName ?? "TripGo"

//

import Foundation



fileprivate struct SSOResult : OAuthData {
  let accessToken: String?

    components.queryItems = [
      URLQueryItem(name: "third_party_app_name",  value: appName),
      URLQueryItem(name: "callback_uri_string",   value: urlScheme + "://sso-uber"),
      URLQueryItem(name: "client_id",             value: clientId),
      URLQueryItem(name: "login_type",            value: "default"),
      URLQueryItem(name: "scope",                 value: "request"),
      URLQueryItem(name: "sdk",                   value: "ios"),
