您只需要使用：

self.dismissViewControllerAnimated(true, completion: {})

其余工作是通过 ARC

为了在调试过程中为您提供帮助，您还可以添加以下代码：

To help you during your debug you can add also this code:

if let app = UIApplication.sharedApplication().delegate as? AppDelegate, let window = app.window {
   if let viewControllers = window.rootViewController?.childViewControllers {
      for viewController in viewController
          print(viewController.debugDescription)
      }
   }
}