         switch panGesture.state {
             case UIGestureRecognizerState.Began:
                 
-                LeftPanState.frameAtStartOfPan = self.leftContainerView.frame
-                LeftPanState.startPointOfPan = panGesture.locationInView(self.view)
-                LeftPanState.wasOpenAtStartOfPan = self.isLeftOpen()
-                LeftPanState.wasHiddenAtStartOfPan = self.isLeftHidden()
+                leftPanState.frameAtStartOfPan = self.leftContainerView.frame
+                leftPanState.startPointOfPan = panGesture.locationInView(self.view)
+                leftPanState.wasOpenAtStartOfPan = self.isLeftOpen()
+                leftPanState.wasHiddenAtStartOfPan = self.isLeftHidden()
                 
-                self.leftViewController?.beginAppearanceTransition(LeftPanState.wasHiddenAtStartOfPan, animated: true)
+                self.leftViewController?.beginAppearanceTransition(leftPanState.wasHiddenAtStartOfPan, animated: true)
                 self.addShadowToView(self.leftContainerView)
                 self.setOpenWindowLevel()
             case UIGestureRecognizerState.Changed:
                 
                 var translation: CGPoint = panGesture.translationInView(panGesture.view!)
-                self.leftContainerView.frame = self.applyLeftTranslation(translation, toFrame: LeftPanState.frameAtStartOfPan)
+                self.leftContainerView.frame = self.applyLeftTranslation(translation, toFrame: leftPanState.frameAtStartOfPan)
                 self.applyLeftOpacity()
                 self.applyLeftContentViewScale()
             case UIGestureRecognizerState.Ended:
                 
-                self.leftViewController?.beginAppearanceTransition(!LeftPanState.wasHiddenAtStartOfPan, animated: true)
+                self.leftViewController?.beginAppearanceTransition(!leftPanState.wasHiddenAtStartOfPan, animated: true)
                 var velocity:CGPoint = panGesture.velocityInView(panGesture.view)
                 var panInfo: PanInfo = self.panLeftResultInfoForVelocity(velocity)
                 

        // Please to override it if necessary
    }
    
    struct LeftPanState {
        static var frameAtStartOfPan: CGRect = CGRectZero
        static var startPointOfPan: CGPoint = CGPointZero
        static var wasOpenAtStartOfPan: Bool = false

        }
    }
    
    private func setUpViewController(targetView: UIView, targetViewController: UIViewController?) {
        if let viewController = targetViewController {
            self.addChildViewController(viewController)
            viewController.view.frame = targetView.bounds
            targetView.addSubview(viewController.view)
            viewController.didMoveToParentViewController(self)
        }
    }
