title: Initializer for conditional binding must have Optional type, not 'NSDictionary'
body: <p>I don't know what it means that I need an optional type. I tried to do the Do/ catch but it still doesn't seem to work. </p>
  
  <pre><code>do {
      let json = try NSJSONSerialization.JSONObjectWithData(data!, options:NSJSONReadingOptions.MutableContainers) as! NSDictionary
  
      if let parseJSON = json {
  
          let userId = parseJSON["userId"] as? String
          if (userId != nil) {
  
              NSUserDefaults.standardUserDefaults().setObject(parseJSON["userFirstName"], forKey: "userFirstName")
              NSUserDefaults.standardUserDefaults().setObject(parseJSON["userLastName"], forKey: "userLastName")
              NSUserDefaults.standardUserDefaults().setObject(parseJSON["userId"], forKey: "userId")
              NSUserDefaults.standardUserDefaults().synchronize()
  
              // take user to a protected page
              /*
              let mainPage = self.storyboard?.instantiateViewControllerWithIdentifier("MainPageViewController") as! MainPageViewController
  
              let mainPageNav = UINavigationController(rootViewController: mainPage)
              let appDelegate = UIApplication.sharedApplication().delegate
  
              appDelegate?.window??.rootViewController = mainPageNav
              */
  
              let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
  
              appDelegate.buildNavigationDrawer()
  
          } else {
  
              // display an alert message
              let userMessage = parseJSON["message"] as? String
              let myAlert = UIAlertController(title: "Alert", message: userMessage, preferredStyle: UIAlertControllerStyle.Alert);
              let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:nil)
              myAlert.addAction(okAction);
              self.presentViewController(myAlert, animated: true, completion: nil)
          }
  
      }
  } catch {
     print(error)
  }
  </code></pre>