ช่วยแนะนำวิธีสร้าง subdirectory ใน Google Drive หน่อยครับ

// Get the API client and construct the service object.
$client = getClient();
$service = new Google_Service_Drive($client);

//Creating a folder
$fileMetadata = new Google_Service_Drive_DriveFile(array(
    'name' => 'IMGUpload',
    'mimeType' => 'application/vnd.google-apps.folder'));
$file = $service->files->create($fileMetadata, array(
    'fields' => 'id'));
printf("Folder ID: %s\n", $file->id);

//Uploads File
$file=$_FILES;

$fileMetadata = new Google_Service_Drive_DriveFile(array(
    	'name' => $file["fileUpload"]["name"],
    	'parents' => array('1P4vY97UnmJMw14Y3KIm-UV_uyr41ywrO')
	));
$content = file_get_contents($file["fileUpload"]["tmp_name"]);
$file = $service->files->create($fileMetadata, array(
    'data' => $content,
    'mimeType' => $file["fileUpload"]["type"],
    'uploadType' => 'multipart',
    'fields' => 'id'));