code: public function installCountries($code = 'US')
      {
          $countryNames = Intl::getRegionBundle()->getCountryNames();
  
          if (!isset($countryNames[$code])) {
              throw new InvalidArgumentException("Invalid default country code '$code'.");
          }
  
          asort($countryNames);
  
          $this->generate(Country::class, $countryNames, $code);
      }
docs: Installs the countries.
  
  @param string $code The default country's code
  
  @throws \Exception