public function removeCSPSource($directive, $source, $reportOnly = null)
    {
        Types::assert(['string' => [$directive, $source]]);

        $csp = &$this->getCSPObject($reportOnly);

        $source = strtolower($source);
        $directive = strtolower($directive);

        if ( ! isset($csp[$directive][$source]))
        {
            return false;
        }

        unset($csp[$directive][$source]);

        return true;
    }