protected function fetchResult(\MongoDB\Driver\Cursor $results, string $username): \stdClass
    {
        $values = $results->toArray();
        if (count($values) > 1) {
            throw new \Caridea\Auth\Exception\UsernameAmbiguous($username);
        } elseif (count($values) == 0) {
            throw new \Caridea\Auth\Exception\UsernameNotFound($username);
        }
        return current($values);
    }