code: def _save_lang(self):
          
          for combobox, (option, _default) in list(self.comboboxes.items()):
              if option == 'interface_language':
                  data = combobox.itemData(combobox.currentIndex())
                  value = from_qvariant(data, to_text_string)
                  break
          try:
              save_lang_conf(value)
              self.set_option('interface_language', value)
          except Exception:
              QMessageBox.critical(
                  self, _("Error"),
                  _("We're sorry but the following error occurred while trying "
                    "to set your selected language:<br><br>"
                    "<tt>{}</tt>").format(traceback.format_exc()),
                  QMessageBox.Ok)
              return
docs: Get selected language setting and save to language configuration file.