title: Declaration is only valid at file scope (extension)
body: <p>i try to make my app just in portrait mode iam using navigationcontroller
  i get this error iam usring <code>Xcode7</code> and <code>Swift 2</code> And Target System <code>IOS 9.3</code><br>
  Declaration is only valid at file scope </p>
  
  <pre><code>        extension UINavigationController {
              public override func supportedInterfaceOrientations() -&gt; Int {
                  return visibleViewController.supportedInterfaceOrientations()
              }
              public override func shouldAutorotate() -&gt; Bool {
                  return visibleViewController.shouldAutorotate()
              }
          }
  
          extension UITabBarController {
              public override func supportedInterfaceOrientations() -&gt; Int {
                  if let selected = selectedViewController {
                      return selected.supportedInterfaceOrientations()
                  }
                  return super.supportedInterfaceOrientations()
              }
              public override func shouldAutorotate() -&gt; Bool {
                  if let selected = selectedViewController {
                      return selected.shouldAutorotate()
                  }
                  return super.shouldAutorotate()
              }
          }
  </code></pre>
  
  <p>Thnx </p>