private static function formatFunction(\ReflectionFunctionAbstract $reflector)
    {
        return \sprintf(
            '<keyword>function</keyword> %s<function>%s</function>(%s)',
            $reflector->returnsReference() ? '&' : '',
            self::formatName($reflector),
            \implode(', ', self::formatFunctionParams($reflector))
        );
    }