code: private function buildPickerService(ContainerBuilder $container)
      {
          $pickerService = $container->getDefinition('metamodels.controller.picker');
          $configs       = $pickerService->getArgument(2);
  
          // Selectable styles in the palette tl_class definitions.
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'w50'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'w50x'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'clr'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'clx'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'long'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'wizard'];
          $configs['PALETTE_STYLE_PICKER'][] = ['cssclass' => 'm12'];
          // Selectable panels in the palette panelLayout definitions.
          $configs['PALETTE_PANEL_PICKER'][] = ['cssclass' => 'search'];
          $configs['PALETTE_PANEL_PICKER'][] = ['cssclass' => 'sort'];
          $configs['PALETTE_PANEL_PICKER'][] = ['cssclass' => 'filter'];
          $configs['PALETTE_PANEL_PICKER'][] = ['cssclass' => 'limit'];
  
          $pickerService->setArgument(2, $configs);
      }
docs: Build the picker service.
  
  @param ContainerBuilder $container The container.
  
  @return void