protected function getAssetBaseUrl()
    {
        $baseUrl = $this->hasOption(self::BASE_OPTION_KEY) ? $this->getOption(self::BASE_OPTION_KEY) : ROOT_URL;

        $baseUrl = trim($baseUrl);
        if(substr($baseUrl, -1) != '/'){
            $baseUrl .= '/';
        }

        return $baseUrl;
    }