Swift 3: fix issue Type "className" does not conform to protocol 'UIDocumentPickerDelegate' - swift

Question

I'm migrating my code from Swift 2 to Swift 3 but my code throws this error: Type "className" does not conform to protocol 'UIDocumentPickerDelegate'. I've migrate many parts of my document as you can see but error stills,
extension className: UIDocumentMenuDelegate {
//Opening the Document Menu
func documentMenu(_ documentMenu: UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {
documentPicker.delegate = self
print ("documentMenu")
self.present(documentPicker, animated: true, completion: nil)
}
func documentMenuWasCancelled(_ documentMenu: UIDocumentMenuViewController) {
}
}
//Using UIDocumentPickerDelegate, error persists here.
extension className: UIDocumentPickerDelegate {
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {
if(controller.documentPickerMode == UIDocumentPickerMode.import){
print ("success")
}
}
}
class className: BaseViewController{
...Tons of code here...
#IBAction func importKeyButtonPressed(_ sender: UIButton) {
let importMenu = UIDocumentMenuViewController(documentTypes: ["public.data","public.text","public.content"], in: UIDocumentPickerMode.import)
var documentPicker = UIDocumentPickerViewController(documentTypes: ["public.txt"], in: UIDocumentPickerMode.import)
documentPicker.delegate = self
documentPicker.modalPresentationStyle = UIModalPresentationStyle.fullScreen
self.present(documentPicker, animated: true, completion: nil)
}
How can I solve it?, I've use all methods that procotol requires. Thanks

Answer 1

I revised your information on this link that has a similar problem.
Cannot conform to STPAddCardViewControllerDelegate since Xcode 8 GM on Swift 3
The problem is the swift compiler than can´t recognize automatically some information. So in this case:
didPickDocumentAt url: URL
Then i follow the problem to this link:
https://bugs.swift.org/browse/SR-2596
In this link the information is that Swift 3 mistake data types, so i research some more and get to this page. The mistaken type in this case is "URL".
Then the solution is in the same page. I write it bellow:
weak var delegate : UIDocumentPickerDelegate?
#available(iOS 8.0, *)
public func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: Foundation.URL ){
//
print("something")
}
To that matter i reproduce the error in my computer, it is caused when diferent imported libraries has the same definition for data types, in this case URL type, which Swift 3 doesnt recognize automatically neither tells correctly the error. So it has to be defined directly.