extension UIView{
func rotate() {
let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
rotation.toValue = NSNumber(value: Double.pi * 2)
rotation.duration = 1
rotation.isCumulative = true
rotation.repeatCount = Float.greatestFiniteMagnitude
self.layer.add(rotation, forKey: "rotationAnimation")
}
}