How can I import file with db extension through document picker?

Question

Actually, I am developing an ios app in which I am providing import and export option for db file. I am done with export option and "MyApp.db" does successfully upload to ICloud. but I am unable to import "MyApp.db". Actually my file is not selectable. Following is the code.

let documentPicker = UIDocumentPickerViewController(documentTypes: ["public.database", "public.content", "public.data"], in: .import)
documentPicker.delegate = self
documentPicker.modalPresentationStyle = .formSheet
self.present(documentPicker, animated: true, completion: nil)

Thanks in advance.