code: def copy_file_clipboard(self, fnames=None):
          
          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))
docs: Copy file(s)/folders(s) to clipboard.