     }
     
     fileprivate func setNeedsNavigationBackground(alpha: CGFloat) {
-        
         let barBackgroundView = navigationBar.subviews[0]
-        
         let valueForKey = barBackgroundView.value(forKey:)
         
         if let shadowView = valueForKey("_shadowView") as? UIView {

            
            objc_setAssociatedObject(self, &AssociatedKeys.navBarBgAlpha, alpha, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            
            //Update UI
            navigationController?.setNeedsNavigationBackground(alpha: alpha)
        }
    }

import UIKit

extension UIColor {
    // System default bar tint color
    open class var defaultNavBarTintColor: UIColor {
        return UIColor(red: 0, green: 0.478431, blue: 1, alpha: 1.0)
    }
