How to use the nativescript-fancyalert.TNSFancyAlert.BACKGROUND_TYPES function in nativescript-fancyalert

public showSuccessCustomEffects() {
    if (isIOS) {
      TNSFancyAlert.showAnimationType =
        TNSFancyAlert.SHOW_ANIMATION_TYPES.SlideInFromLeft;
      TNSFancyAlert.hideAnimationType =
        TNSFancyAlert.HIDE_ANIMATION_TYPES.SlideOutToRight;
      TNSFancyAlert.backgroundType = TNSFancyAlert.BACKGROUND_TYPES.Blur;
      TNSFancyAlert.soundURL = "bell.mp3";
      TNSFancyAlert.showSuccess(
        "Sound?",
        "You can use sound and customize many aspects like animation in/out, color, background style and much more.",
        "Amazing!"
      );
      this.reset();
    }
  }