title: Navigation pushViewController is not working
body: <p>i have login view controller. when usersingin i' showing popup for that i </p>
  
  <p>refereed 
  <a href="https://www.youtube.com/watch?v=S5i8n_bqblE" rel="nofollow noreferrer">https://www.youtube.com/watch?v=S5i8n_bqblE</a> i can achieved that. 
  popup had button when i click the button navigation to next view controller 
  but its now working when i am clicking that action is performing but its not  navigating to next view controller wher  i did mistake </p>
  
  <pre><code>Singin 
  
  class DigitalGateViewController: NANavigationViewController
  {
  
        @IBAction func singin(_ sender: UIButton)
          {
                      let lv = NAViewPresenter().activityVC()
                      self.present(lv, animated: true)
           }
  
  }
  
   this is popupviewcontroller 
  
    class ActivityViewController: NANavigationViewController {
  
  
  
      @IBAction func okbuttonclick() {
             let dv = NAViewPresenter().myGuestListVC()
             // self.navigationController?.pushViewController(dv, animated: true)
              }
      }
  </code></pre>
  
  <p>its not push to textview controller in swift </p>