code: private function prepareCountryCodes($blockedCountries)
      {
          $result = '';
          $countriesArray = [];
          $countries = '';
  
          if ($blockedCountries != null) {
              foreach ($blockedCountries as $key => $value) {
                  $countriesArray[] = $value['value'];
              }
              $countries = implode(',', $countriesArray);
          }
  
          $this->configWriter->save(
              Config::XML_FASTLY_BLOCK_BY_COUNTRY,
              $countries,
              'default',
              '0'
          );
  
          if ($countries != '') {
              $blockedCountriesPieces = explode(",", $countries);
              foreach ($blockedCountriesPieces as $code) {
                  $result .= ' client.geo.country_code == "' . $code . '" ||';
              }
          }
  
          return $result;
      }
docs: Prepares blocked countries VCL snippet
  
  @param $blockedCountries
  @return string