 
     let fadeOutDuration: TimeInterval = 2.0
 
-    var completion: ((animation: KenBurnsAnimation) -> ())?
-    var willFadeOut: ((animation: KenBurnsAnimation) -> ())?
+    var completion: ((_ animation: KenBurnsAnimation) -> ())?
+    var willFadeOut: ((_ animation: KenBurnsAnimation) -> ())?
 
     init(targetImage: UIImageView, zoomIntensity: Double, durationRange: DurationRange, pansAcross: Bool) {
         self.targetImage = targetImage

            return
        }
        guard let willFadeOut = self.willFadeOut else { return }
        willFadeOut(animation: self)
        self.willFadeOut = nil // never call it again
    }


            return
        }

        updatesDisplayLink.add(to: RunLoop.main, forMode: .commonModes)
        startNewAnimation()
    }

