title: Cannot assign a value of type '(String!, Bool, [AnyObject]!, NSError!)->Void to a value of type UIActivityViewControllerCompletionWithItemsHandler?'
body: <p>I have the following lines of code in my project...</p>
  
  <pre><code>@IBAction func shareMeme(sender: UIBarButtonItem) {
  
      let newMeme = save()
      let memedImage = newMeme.memedImage
      let activityViewController = UIActivityViewController(activityItems: [memedImage], applicationActivities: nil)
  
      presentViewController(activityViewController, animated: true, completion: nil)
  
      activityViewController.completionWithItemsHandler = {(type: String!, completed: Bool, returnedItems: [AnyObject]!, error: NSError!) -&gt; Void in
  
          dispatch_async(dispatch_get_main_queue()){
              self.presentingViewController?.dismissViewControllerAnimated(true, completion: nil)
          }
      }
  }
  </code></pre>
  
  <p>I keep getting a compiler error "Cannot assign a value of type '(String!, Bool, [AnyObject]!, NSError!) -> Void' to a value of type 'UIActivityViewControllerCompletionWithItemsHandler?'" referring to the following line of code...</p>
  
  <pre><code>    activityViewController.completionWithItemsHandler = {(type: String!, completed: Bool, returnedItems: [AnyObject]!, error: NSError!) -&gt; Void in
  </code></pre>
  
  <p>Any suggestions would be appreciated. </p>