public function isAccessTokenRevoked($tokenId)
    {
        /** @var \Concrete\Core\Entity\OAuth\AccessToken $token */
        $token = $this->find($tokenId);
        if (!$token) {
            // The token was manually removed.
            return true;
        }

        $now = new \DateTime('now');
        // If we have a token and it has expired...
        if ($token && $token->getExpiryDateTime() < $now) {
            return true;
        }

        return false;
    }