Necesito abrirUIDocumentPickerViewController Debería permitir al usuario seleccionar todo tipo de archivos. es decir. (. pdf, .doc) archivos que utilicéUIDocumentPickerViewController método. mi código:

UIDocumentPickerDelegate, UIDocumentMenuDelegate en mi declaración de clase

//subir archivo

func OpenFile(){

    let importMenu = UIDocumentMenuViewController(documentTypes: [String(kUTTypePNG),String(kUTTypeImage)], in: .import)
    importMenu.delegate = self
    importMenu.modalPresentationStyle = .fullScreen
    self.present(importMenu, animated: true, completion: nil)

}
@available(iOS 8.0, *)
public func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {        
    let cico = url as URL
    print("The Url is : \(cico)")

    do {
        let weatherData = try NSData(contentsOf: cico, options: NSData.ReadingOptions())
        print(weatherData)
        let activityItems = [weatherData]
        let activityController = UIActivityViewController(activityItems: activityItems, applicationActivities: nil)
        if UI_USER_INTERFACE_IDIOM() == .phone {
            self.present(activityController, animated: true, completion: { _ in })
        }
        else {
            let popup = UIPopoverController(contentViewController: activityController)
            popup.present(from: CGRect(x: CGFloat(self.view.frame.size.width / 2), y: CGFloat(self.view.frame.size.height / 4), width: CGFloat(0), height: CGFloat(0)), in: self.view, permittedArrowDirections: .any, animated: true)
        }

    } catch {
        print(error)
    }

    //optional, case PDF -> render
    //displayPDFweb.loadRequest(NSURLRequest(url: cico) as URLRequest)      


}

@available(iOS 8.0, *)
public func documentMenu(_ documentMenu:     UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {

    documentPicker.delegate = self
    present(documentPicker, animated: true, completion: nil)        
} 


func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {

    print(" cancelled by user")

    dismiss(animated: true, completion: nil)        

}

En este código, la aplicación se bloqueará. la razón esTerminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'You cannot initialize a UIDocumentPickerViewController except by the initWithDocumentTypes:inMode: and initWithURL:inMode: initializers.

No sé cómo inicializar elinitWithDocumentTypes:inMode. Soy nuevo en iOS, ¿alguien me ayuda? Podrías ayudarme..