two Error in WKTabBarController.swift swift 4

[h-o-sein]

error in WKTabBarController.swift

• 1- Error
  Argument of '#selector' refers to instance method 'didChangeOrientation' that is not exposed to Objective-C

NotificationCenter.default.addObserver( self, selector: #selector(didChangeOrientation(_:)), name: NSNotification.Name.UIApplicationDidChangeStatusBarOrientation, object: nil) if let vc = tabBarController(self, viewControllerAtIndex: 0) { changeViewController(vc) }
error:
selector: #selector(didChangeOrientation(_:)),

and

• 2- Error
  Contextual closure type '(_, WKTabBarItem) -> _' expects 2 arguments, but 1 was used in closure body

open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { let proportion = tabBarItems[indexPath.row].proportion let sum = tabBarItems.reduce(0.0) { $0.0 + $0.1.proportion } return CGSize(width: collectionView.bounds.width * CGFloat(proportion / sum), height: collectionView.bounds.height) }

error :
let sum = tabBarItems.reduce(0.0) { $0.0 + $0.1.proportion }