         }
     }
 
-    // MARK: - UITableViewDataSource
+}
+
+// MARK: - UITableViewDataSource
+
+extension MasterViewController {
 
     override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         return sampleData.count

    }

}


        PreviewDetail(title: "Large", preferredHeight: 0.0) // 0.0 to get the default height.
    ]

}

// MARK: - UIViewController

extension MasterViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
