{
    "helloWorld": "¡Hola Mundo!"
}

Now, run flutter gen-l10n so that codegen takes place. You should see generated files in
${FLUTTER_PROJECT}/.dart_tool/flutter_gen/gen_l10n.
Alternatively, you can also run flutter gen-l10n to generate the same
files without running the app.

Add the import statement on app_localizations.dart and AppLocalizations.delegate
in your call to the constructor for MaterialApp.

    
import 'package:flutter_gen/gen_l10n/app_localizations.dart';