             return willGetTransitionDelegate()
         }
     }
+    public var showCustomAnimation: Bool {
+        set {
+            willSetShowCustomAnimation(showCustomAnimation)
+        }
+        get {
+            return willGetShowCustomAnimation()
+        }
+    }
     public func showHistory() {}
     public func setHistoryBackgroundColor(color: UIColor) {}
     public func contentView() -> UIView? { return nil }

    
    private weak var _navigationDelegate: SAHistoryNavigationViewControllerDelegate?
    private weak var _transitionDelegate: SAHistoryNavigationViewControllerTransitionDelegate?
    
    required public init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

        if let animationController = _transitionDelegate?.navigationController?(self, animationControllerForOperation: operation, fromViewController: fromVC, toViewController: toVC) {
            return animationController
        }

        if !showCustomAnimation {
          return nil
        }

        return SAHistoryNavigationTransitionController(operation: operation)
    }
}