public function loadCountries()
    {
        $this->countriesJson = $this->loadCountriesJson();

        $overload = $this->helper->loadJsonFiles($this->helper->dataDir('countries/overload'))->mapWithKeys(function ($country, $code) {
            return [upper($code) => $country];
        });

        $this->countriesJson = $this->countriesJson->overwrite($overload);

        return $this->countriesJson;
    }