Copy file(s)/folders(s) to clipboard.

def copy_file_clipboard(self, fnames=None):
        """Copy file(s)/folders(s) to clipboard."""
        if fnames is None:
            fnames = self.get_selected_filenames()
        if not isinstance(fnames, (tuple, list)):
            fnames = [fnames]
        try:
            file_content = QMimeData()
            file_content.setUrls([QUrl.fromLocalFile(_fn) for _fn in fnames])
            cb = QApplication.clipboard()
            cb.setMimeData(file_content, mode=cb.Clipboard)
        except Exception as e:
            QMessageBox.critical(self,
                                 _('File/Folder copy error'),
                                 _("Cannot copy this type of file(s) or "
                                     "folder(s). The error was:\n\n")
                                 + to_text_string(e))