如何在Swift中向tweet添加位置？

我正在使用Social Framework能够将我的应用程序中的内容共享到Twitter。我希望能够在推文中添加位置。这是我的代码：

if SLComposeViewController.isAvailableForServiceType(SLServiceTypeTwitter) {
  let twitterComposeVC = SLComposeViewController(forServiceType: SLServiceTypeTwitter)   
  twitterComposeVC.setInitialText("I found a really nice spot. Check it out here")          
  self.presentViewController(twitterComposeVC, animated: true, completion: nil)
} else {
  self.showAlertMessage("Please make sure you're logged into Twitter in your device settings")
}