Google Cloud Datastore Error The library is this: https://github.com/google/google-api-php-client throw Google_Service_Exception at src/Google/Http/REST.php on line 75 Error calling POST https://www.googleapis.com/datastore/v1beta2/datasets/btspprt/lookup: (400) app s~btspprt cannot access app btspprt's data

datastore.php

<?php
/**
 * 
 * The library is this: https://github.com/google/google-api-php-client
 * 
 * 
 * throw Google_Service_Exception at src/Google/Http/REST.php on line 75
 * 
 * Error calling POST https://www.googleapis.com/datastore/v1beta2/datasets/btspprt/lookup: (400) app s~btspprt cannot access app btspprt's data
 * 
 */
 
$creds = new Google_Auth_AssertionCredentials('__user__@developer.gserviceaccount.com', array(
	'https://www.googleapis.com/auth/datastore',
	'https://www.googleapis.com/auth/userinfo.email'
), file_get_contents('__public_key__-privatekey.p12'));

$client = new Google_Client();
$client->setAssertionCredentials($creds);

$datastore = new Google_Service_Datastore($client);

$AppId = '__application_id__';

$partitionId = new Google_Service_Datastore_PartitionId();
$partitionId->setDatasetId($AppId);
$partitionId->setNamespace('User');

$path = new Google_Service_Datastore_KeyPathElement();
$path->setId('__entity_id_as_integer__');
$path->setKind('User');

$key = new Google_Service_Datastore_Key();
$key->setPartitionId($partitionId);
$key->setPath($path);

$keys = array($key);

$readOptions = new Google_Service_Datastore_ReadOptions();
$readOptions->setReadConsistency("DEFAULT");

$lookupRequest = new Google_Service_Datastore_LookupRequest();
$lookupRequest->setKeys($keys);
$lookupRequest->setReadOptions($readOptions);

$datastore->datasets->lookup($AppId, $lookupRequest);