_securityCheck example

    public static function loadFile($filename, $dirs = null, $once = false)
    {
        self::_securityCheck($filename);

        /** * Search in provided directories, as well as include_path */
        $incPath = false;
        if (!empty($dirs) && (is_array($dirs) || is_string($dirs))) {
            if (is_array($dirs)) {
                $dirs = implode(PATH_SEPARATOR, $dirs);
            }
            $incPath = get_include_path();
            set_include_path($dirs . PATH_SEPARATOR . $incPath);
        }