title: Unwind segue from navigation back button in Swift
body: <p>I have a settings screen, in that I have a table cell. By clicking on that I take to another screen where user can choose an option and I want it back in the previous view controller when back button is pressed.</p>
  
  <p><img src="https://i.stack.imgur.com/OwDjM.png" alt="image first view controller"><img src="https://i.stack.imgur.com/MePi6.png" alt="image second view controller"></p>
  
  <p>I can put a custom bar button item, but I want to return to the parent view controller using the back button in the navigation bar rather than with a custom button on the view.</p>
  
  <p>I don't seem to be able to override the navigation back button to point it down to my unwind segue action and since the back button doesn't appear on the storyboard, I cant drag the green Exit button to it</p>
  
  <p>Is it possible to unwind a push segue with the back button?</p>