public function getToken($id)
    {
        if ($id) {
            $ownerClass = $this->tokenConfig['owner'];
            $owner = DataObject::get_by_id($ownerClass, $id);

            if ($owner) {
                $tokenDBColumn = $this->tokenConfig['DBColumn'];
                return $owner->{$tokenDBColumn};
            } else {
                user_error("API Token owner '$ownerClass' not found with ID = $id", E_USER_WARNING);
            }
        } else {
            user_error("TokenAuthenticator::getToken() requires an ID as argument.", E_USER_WARNING);
        }
    }