Nelmio\SecurityBundle\ContentSecurityPolicy\ContentSecurityPolicyParser::quoteKeywords PHP Method

    protected function quoteKeywords(array $sourceList)
    {
        $keywords = $this->keywords;
        return array_map(function ($source) use($keywords) {
            if (in_array($source, $keywords, true)) {
                return sprintf("'%s'", $source);
            }
            return $source;
        }, $sourceList);
    }