anchor.diff:  import 'package:gallery/l10n/gallery_localizations.dart';
   import 'package:gallery/themes/material_demo_theme_data.dart';
   
  +const _docsBaseUrl = 'https://api.flutter.dev/flutter';
  +
   class GalleryDemo {
     GalleryDemo({
       @required this.title,
  
positive.code: }
  
  List<GalleryDemo> materialDemos(BuildContext context) {
    return [
      GalleryDemo(
        title: GalleryLocalizations.of(context).demoBottomAppBarTitle,
        icon: GalleryIcons.bottomAppBar,
        subtitle: GalleryLocalizations.of(context).demoBottomAppBarSubtitle,
        configurations: [
          GalleryDemoConfiguration(
            title: GalleryLocalizations.of(context).demoBottomAppBarTitle,
            description:
                GalleryLocalizations.of(context).demoBottomAppBarDescription,
            documentationUrl:
                'https://api.flutter.dev/flutter/material/BottomAppBar-class.html',
            buildRoute: (_) => BottomAppBarDemo(),
            code: CodeSegments.bottomAppBarDemo,
          ),
        ],
      ),
      GalleryDemo(
        title: GalleryLocalizations.of(context).demoBottomNavigationTitle,
        icon: GalleryIcons.bottomNavigation,
        subtitle: GalleryLocalizations.of(context).demoBottomNavigationSubtitle,
        configurations: [
          GalleryDemoConfiguration(
            title: GalleryLocalizations.of(context)
                .demoBottomNavigationPersistentLabels,
            description:
                GalleryLocalizations.of(context).demoBottomNavigationDescription,
            documentationUrl:
                'https://api.flutter.dev/flutter/material/BottomNavigationBar-class.html',
            buildRoute: (_) =>
                BottomNavigationDemo(type: BottomNavigationDemoType.withLabels),
            code: CodeSegments.bottomNavigationDemo,
          ),
          GalleryDemoConfiguration(
            title: GalleryLocalizations.of(context)
                .demoBottomNavigationSelectedLabel,
            description:
                GalleryLocalizations.of(context).demoBottomNavigationDescription,
            documentationUrl:
                'https://api.flutter.dev/flutter/material/BottomNavigationBar-class.html',
            buildRoute: (_) => BottomNavigationDemo(
                type: BottomNavigationDemoType.withoutLabels),
            code: CodeSegments.bottomNavigationDemo,
  
negative.code:       ],
      ),
      GalleryDemo(
        title: localizations.demoSelectionControlsTitle,
        icon: GalleryIcons.checkBox,
        subtitle: localizations.demoSelectionControlsSubtitle,
        configurations: [
          GalleryDemoConfiguration(
            title: localizations.demoSelectionControlsCheckboxTitle,
            description: localizations.demoSelectionControlsCheckboxDescription,
            documentationUrl: '$_docsBaseUrl/material/Checkbox-class.html',
            buildRoute: (context) => SelectionControlsDemo(
              type: SelectionControlsDemoType.checkbox,
            ),
            code: CodeSegments.selectionControlsDemoCheckbox,
          ),
          GalleryDemoConfiguration(
            title: localizations.demoSelectionControlsRadioTitle,
            description: localizations.demoSelectionControlsRadioDescription,
            documentationUrl: '$_docsBaseUrl/material/Radio-class.html',
            buildRoute: (context) => SelectionControlsDemo(
              type: SelectionControlsDemoType.radio,
            ),
            code: CodeSegments.selectionControlsDemoRadio,
          ),
          GalleryDemoConfiguration(
            title: localizations.demoSelectionControlsSwitchTitle,
            description: localizations.demoSelectionControlsSwitchDescription,
            documentationUrl: '$_docsBaseUrl/material/Switch-class.html',
            buildRoute: (context) => SelectionControlsDemo(
              type: SelectionControlsDemoType.switches,
            ),
  