title: didSelect mapView annotation not working properly
body: <p>When I tap the map annotation it will display the more information about the pin.</p>
  
  <p>On my first tap attempt ,when I tap the map annotation it will run successfully and it will display the correct information but when I hit back button and do my second tap attempt to the same pin the fatal error occured and its saying that 'Unexpectedly Found nil while unwrapping and optional value',</p>
  
  <p>based on my observation and I made some troubleshooting and debugging, I found out that the fatal error only occurred when I didn't tap to the map first before I tap the map pin OR if I don't tap different pin (if I tap the same pin for the second attempt without tapping the map first error occurred)</p>
  
  <p><code>MyAnnotations</code> Class:</p>
  
  <pre><code>import MapKit
  
  class MyAnnotations: NSObject,MKAnnotation{
  
      var coordinate: CLLocationCoordinate2D
      var title: String?
      var subtitle: String?
      var img: String?
      var court_id: Int?
      var class_name: String?
  
      init(coordinate:CLLocationCoordinate2D, title: String?, subtitle: 
      String?, img:String?, court_id: Int?, class_name: String?){
          self.coordinate = coordinate
          self.title = title
          self.subtitle = subtitle
          self.img = img
          self.court_id = court_id
          self.class_name = class_name
  
          super.init()
      }
  }
  </code></pre>
  
  <p>My <code>func mapView(_:didSelect:)</code>:</p>
  
  <pre><code>func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView){
      let ibp = view.annotation as? MyAnnotations
      print(ibp!)
      ibp_id = (ibp?.court_id)!
      IdentifierCell = "pin_IBP"
      performSegue(withIdentifier: "map_ibp_info", sender: self)
  }
  </code></pre>