title: Streaming audio from parse in Swift 3
body: <p>I'm using Back4app as Parse server
  I'm trying to stream audio from Prase 
  everything works fine , but if I click on any index (except index 0) on tableview I got error "fatal error: unexpectedly found nil while unwrapping an Optional value"</p>
  
  <p>I don't know why when I click on Index 0 it work fine but any other index I got error !</p>
  
  <pre><code>func grabSong() {        
      let SongQuery = PFQuery(className: "Songs")
  
      SongQuery.getObjectInBackground(withId:iDArray[SelectedSongNumber!] ,block: { (object : PFObject?, error : Error?) -&gt;  Void in           
          if let AudioFileURLTemp : PFFile = object?.value(forKey: "SongFile") as? PFFile {            
              print(AudioFileURLTemp)
  
              audioP = AVPlayer(url: NSURL(string: AudioFileURLTemp.url!) as! URL)            
              audioP.play()        
          }       
      })
  }
  </code></pre>
  
  <p>I got the error on this line:</p>
  
  <pre><code>audioP = AVPlayer(url: NSURL(string: AudioFileURLTemp.url!) as! URL)
  </code></pre>