         fileprivate static var instances: [Block] = []
     }
     
-    var completion: (()->Void)?
+    private var completion: (()->Void)?
     
     init(_ completion: @escaping ()->Void) {
         self.completion = completion


class BasicAnimationBlock: Block {
    
    let animationBlock: AnimationBlock
    
    @discardableResult init(duration: TimeInterval, delay: TimeInterval, animationBlock: @escaping AnimationBlock, completion:  ((Bool)->Void)? = nil) {
        self.animationBlock = animationBlock

    }
    
    @objc func animationBlock(_ sender: Timer) {
        animationBlock?()
        animationBlock = nil
    }
}
