Play.swift

func play(sound: String, ofType type: SoundExtension) {
   if let soundID = notificationSoundLookupTable[sound] {
      AudioServicesPlaySystemSound(soundID)
   } else {
      if let soundURL : CFURL = Bundle.main.url(forResource: sound,       withExtension: type.rawValue) as CFURL? {
         var soundID  : SystemSoundID = 0
         let osStatus : OSStatus = AudioServicesCreateSystemSoundID(soundURL, &soundID)
         if osStatus == kAudioServicesNoError {
            AudioServicesPlaySystemSound(soundID);
            notificationSoundLookupTable[sound] = (soundID)
         }else{
            // This happens in exceptional cases
            // Handle it with no sound or retry
         }
      }
   }
}