title: Navigation Left bar button item with back button
body: <p>I want to add left bar button item in <code>navaigationBar</code>.
  I have back button sign (do not have any text) in left side and when I add <code>leftBarButtonItem</code> then I can not see the back button.</p>
  
  <p>How can I solve this problem.</p>
  
  <p>This is my code:</p>
  
  <pre><code>let phonePhoto = UIButton()
  phonePhoto.setImage(UIImage(named: "navigationPhone"), for: UIControlState())
  phonePhoto.frame = CGRect(x: 0, y: 0, width: 40, height: 40)
  phonePhoto.addTarget(self, action: #selector(userEdit), for: .touchUpInside)
  
  let userPhone = UIBarButtonItem()
  userPhone.customView = phonePhoto
  
  self.navigationItem.leftBarButtonItem = userPhone
  </code></pre>