When passing an invalid token, I am getting a PHP error. The current line is: ``` if (!self::verify("{$headb64}.{$bodyb64}", $sig, $key->getKeyMaterial(), $header->alg)) { throw new SignatureInvalidException('Signature verification failed'); } ``` But as far as I can see, SignatureInvalidException is not available in this file I updated to use the included `UnexpectedValueException`. Please let me know if I have this wrong or if there really is some code error.