Controller/Adminhtml/FastlyCdn/Blocking/UpdateBlocking.php
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 $result;
    }
private function prepareCountryCodes($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;
    }
Prepares blocked countries VCL snippet

@param $blockedCountries
@return string