title: Warning in Xcode 8: Instance method nearly matches optional requirement
body: <p>I am trying to implement local notifications in iOS10, and so far <a href="https://stackoverflow.com/questions/38954496/unusernotificationcenter-did-receive-response-with-completion-handler-is-never-c">it is not working</a>. </p>
  
  <p>I get this warning around my delegate methods:</p>
  
  <pre><code>Instance method 'userNotificationCenter(_:didReceive:withCompletionHandler:)'     
  nearly matches optional requirement 'userNotificationCenter(_:didReceive:withCompletionHandler:)'
  of protocol 'UNUserNotificationCenterDelegate'
  </code></pre>
  
  <p>As solution xcode suggests two options:
  1.make it private
  2.make it @nonobjc</p>
  
  <p>Why is that? Why do I need to do it? And most important, how to make these methods work?</p>
  
  <p><a href="https://i.stack.imgur.com/Eqxrk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Eqxrk.png" alt="enter image description here"></a></p>