       gView.startColor = ColorType(rawValue: self.colorValues.value(at: 0))?.color
       gView.endColor = ColorType(rawValue: self.colorValues.value(at: 0))?.color
     }
-    var navigationBar = self.navigationController?.navigationBar as? DesignableNavigationBar
+    let navigationBar = self.navigationController?.navigationBar as? DesignableNavigationBar
     navigationBar?.copyGradient(from: gView)
     navigationBar?.configureGradient()
   }
 
   override func viewWillDisappear(_ animated: Bool) {
     super.viewWillDisappear(animated)
-    var navigationBar = self.navigationController?.navigationBar as? DesignableNavigationBar
+    let navigationBar = self.navigationController?.navigationBar as? DesignableNavigationBar
     navigationBar?.resetGradient()
     navigationBar?.setBackgroundImage(nil, for: .default)
   }


fileprivate extension GradientDesignable {

  mutating func copyGradient(from designable: GradientDesignable) {
    predefinedGradient = designable.predefinedGradient
    startColor = designable.startColor
    endColor = designable.endColor
    startPoint = designable.startPoint
  }

  mutating func resetGradient(defaultStartPoint: GradientStartPoint = .top) {
    predefinedGradient = nil
    startColor = nil
    endColor = nil

    }
    gView.configureGradient()

    let navigationBar = self.navigationController?.navigationBar as? DesignableNavigationBar
    navigationBar?.copyGradient(from: gView)
    navigationBar?.configureGradient()
  }
