如何让我的backgroundImageView成为可拖动的而不是主视图

let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
backgroundImageView.addGestureRecognizer(panGesture)

@objc func handlePan(_ gesture: UIPanGestureRecognizer) {
    let translation = gesture.translation(in: self.view)
    backgroundImageView.center = CGPoint(x: backgroundImageView.center.x + translation.x, y: backgroundImageView.center.y + translation.y)
    gesture.setTranslation(CGPoint.zero, in: self.view)
}

backgroundImageView.isUserInteractionEnabled = true