docs: def _on_export_config(self, *args):
          """Callback method the the export button was clicked
  
          Shows dialogs allowing to export the configurations into separate files
          """
          response = self._config_chooser_dialog("Export configuration",
                                                 "Please select the configuration file(s) to be exported:")
          if response == Gtk.ResponseType.REJECT:
              return
  
          def handle_export(dialog_text, path, config_m):
              chooser = Gtk.FileChooserDialog(dialog_text, None,
                                              Gtk.FileChooserAction.SAVE,
                                              (Gtk.STOCK_CANCEL, Gtk.ResponseType.CANCEL,
                                               Gtk.STOCK_SAVE_AS, Gtk.ResponseType.ACCEPT))
              chooser.set_current_folder(path)
              response = chooser.run()
              if response == Gtk.ResponseType.ACCEPT:
                  config_file = chooser.get_filename()
                  if not config_file:
                      logger.error("Configuration could not be exported! Invalid file name!")
                  else:
                      if ".yaml" not in config_file:
                          config_file += ".yaml"
                      if config_m.preliminary_config:
                          logger.warning("There are changes in the configuration that have not yet been applied. These "
                                      "changes will not be exported.")
                      self._last_path = dirname(config_file)
                      config_dict = config_m.as_dict()
                      config_copy = yaml_configuration.config.DefaultConfig(str(config_dict))
                      config_copy.config_file_path = config_file
                      config_copy.path = self._last_path
                      try:
                          config_copy.save_configuration()
                          logger.info("Configuration exported to {}" .format(config_file))
                      except IOError:
                          logger.error("Cannot open file '{}' for writing".format(config_file))
              elif response == Gtk.ResponseType.CANCEL:
                  logger.warning("Export Config canceled!")
              chooser.destroy()
  
          if self._core_checkbox.get_active():
              handle_export("Select file for core configuration", self._last_path, self.core_config_model)
  
          if self._gui_checkbox.get_active():
              handle_export("Select file for GUI configuration.", self._last_path, self.gui_config_model)