public function get_not_whitelisted($types, $whitelist) {

        $whitelistedtypes = $this->expand($whitelist, true, true);

        if (empty($whitelistedtypes) || $whitelistedtypes == ['*']) {
            return [];
        }

        $giventypes = $this->normalize_file_types($types);

        if (empty($giventypes)) {
            return [];
        }

        return array_diff($giventypes, $whitelistedtypes);
    }