Bulk get does not work

PHP SDK
1

the documentation here:
http://docs.couchbase.com/developer/php-2.0/bulk-operations.html
states that bulk get operations work with an array of ids but nothing is returned.

This is how I am using it.

$cluster = new CouchbaseCluster('http://127.0.0.1:8091');
$bucket = $cluster->openBucket('mybucket');
$doc_ids = array("test::bulkget1","test::bulkget2");
try {
    $res = $bucket->get($doc_ids);
    var_dump($res);
} catch (CouchbaseException $e) {
    unset($error);
    $error['code'] = $e->getCode();
    $error['message'] = $e->getMessage();
    unset($result);
    $result['error'] = $error;
    echo json_encode($result);
}

The docs exist on the server but nothing is returned.