iOS Xcode File picker and uploading - ios

Question

I am new into this Xcode iOS stuff, I am trying to build a file uploader, you pick a file and then you upload to server. Currently I am stuck at picking the file. I have used some code found on this website, but I am getting some errors.
Class starts like this:
class DocumentsController: UIViewController, UIDocumentMenuDelegate,UIDocumentPickerDelegate,UINavigationControllerDelegate
Methods used are:
#objc func pickFile() {
let importMenu = UIDocumentMenuViewController(documentTypes: [String(kUTTypePDF), String(kUTTypePNG), String(kUTTypeJPEG)], in: .import)
importMenu.delegate = self
importMenu.modalPresentationStyle = .formSheet
self.present(importMenu, animated: true, completion: nil)
}
public func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
guard let myURL = urls.first else {
return
}
print("import result : \(myURL)")
}
public func documentMenu(_ documentMenu:UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {
documentPicker.delegate = self
present(documentPicker, animated: true, completion: nil)
}
func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
print("view was cancelled")
dismiss(animated: true, completion: nil)
}
In the documentPicker method I have two errors:
'URL' is ambiguous for type lookup in this context <- for urls: [URL]
Type of expression is ambiguous without more context <- for guard let myURL = urls.first
If I replace URL with String or NSURL it gets past that, the build is successful, the app on the simulator is running (Iphone 8 plus), I can open the picker, choose a file, but then nothing happens. It just closes the picker and that's it. documentPicker method doesn't trigger. Out of the 4 methods only pickFile and documentMenu are triggering.
Xcode version is 13.3.1