order by not working in Google App Engine php

I have used Google App Enginein PHP with ndb

Now I have to save data a model and fetch from that

$query = $datastore->query()
    ->kind('warehouse'); 

$result = $datastore->runQuery($query);

warehouse has name and address fields

and this query is working well

when I try this

use Google\Cloud\Datastore\Query\Query;

$query = $datastore->query()
    ->kind('warehouse')->order('created', Query::ORDER_DESCENDING);
$result = $datastore->runQuery($query);

This is not working, Name has StringProperty. how can I get data with order desc from ndb

https://cloud.google.com/datastore/docs/concepts/queries

Create a index.yaml file and put this code in this

indexes:
- kind: warehouse
  ancestor: no
  properties:
  - name: created
    direction: desc

if you want to apply filter

 $query = $datastore->query()
 ->kind('warehouse')->filter->('address'=>'USA')->order('created', Query::ORDER_DESCENDING);

then in index.yaml

indexes:
- kind: warehouse
  ancestor: no
  properties:
  - name: address 
  - name: created
    direction: desc

and upload it

gcloud datastore indexes create index.yaml