如何在UIDocumentPickerViewController中更新框架大小的样式

let documentPicker = UIDocumentPickerViewController(documentTypes: ["public.item"], in: .import)
documentPicker.delegate = self

func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
    // 处理选中的文档
    // 更新框架大小的样式
}

func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {
    // 处理选中的文档
    // 更新框架大小的样式
}

controller.view.backgroundColor = UIColor.white
controller.view.layer.borderWidth = 1.0
controller.view.layer.borderColor = UIColor.black.cgColor
controller.view.layer.shadowColor = UIColor.gray.cgColor
controller.view.layer.shadowOpacity = 0.5