func tableView ( tableView :  UITableView ,  didSelectRowAtIndexPath indexPath :  NSIndexPath )  {          let eventVC =  EKEventViewController ()          eventVC . event =  eventItems [ indexPath . row ]          eventVC . allowsEditing =  true          eventVC . allowsCalendarPreview =  true          eventVC . delegate  =  self         self . presentViewController ( eventVC ,  animated :  true ,  completion :  nil )  }  위와 같이 했는데 Done 버튼이 나타나지 않음  아래와 같이 네이게이션 컨트롤러를 추가하고 모달 스타일을 페이지 시트로 변경하니 잘 나옴  func tableView(tableView: UITableView , didSelectRowAtIndexPath indexPath: NSIndexPath ) {     let eventVC = EKEventViewController ()     eventVC.event = eventItems[indexPath.row]     eventVC.allowsEditing = true      eventVC.allowsCalendarPreview = true      eventVC. delegate  = self      let nav = UINavigationController (rootViewController: eventVC)     nav.modalPresentationStyle = . PageSheet      self.presentViewController(nav, animated: true , completion: nil) }