private function askDefaultLocale(): string
    {
        $io = new SymfonyStyle(new ArgvInput(), new ConsoleOutput());

        return $io->ask(
            'Please input the default locale for existing layouts',
            '',
            static function (string $locale): string {
                if (!Locales::exists($locale)) {
                    throw new RuntimeException('Specified locale is not valid');
                }

                return $locale;
            }
        );
    }