An Objekt aus einem Array kommen

$ergebnis = $shipments[0]->{'shipmentLabel:Dhl\Sdk\Paket\Bcs\Service\ShipmentService\Shipment:private'};

var_export($shipments);

array (
  0 => 
  Dhl\Sdk\Paket\Bcs\Service\ShipmentService\Shipment::__set_state(array(
     'sequenceNumber' => '0',
     'shipmentNumber' => '123',
     'returnShipmentNumber' => '',
     'shipmentLabel' => 'Testergebnis',
     'returnLabel' => '',
     'exportLabel' => '',
     'codLabel' => '',
  )),
)

$logger = new \Psr\Log\NullLogger();

$serviceFactory = new \Dhl\Sdk\Paket\Bcs\Service\ServiceFactory();
$service = $serviceFactory->createShipmentService($authStorage, $logger, $sandbox = true);

$orderConfiguration = new \Dhl\Sdk\Paket\Bcs\Service\ShipmentService\OrderConfiguration(
    $printOnlyIfCodable = true,
    $combinedPrinting = null,
    $docFormat = \Dhl\Sdk\Paket\Bcs\Api\Data\OrderConfigurationInterface::DOC_FORMAT_PDF,
    $printFormat = \Dhl\Sdk\Paket\Bcs\Api\Data\OrderConfigurationInterface::PRINT_FORMAT_A4
);

$requestBuilder = new \Dhl\Sdk\Paket\Bcs\RequestBuilder\ShipmentOrderRequestBuilder();
$requestBuilder->setShipperAccount($billingNumber = '22222222220101');
$requestBuilder->setShipperAddress(
    $company = 'DHL',
    $country = 'DE',
    $postalCode = '53113',
    $city = 'Bonn',
    $street = 'Charles-de-Gaulle-Straße',
    $streetNumber = '20'
);
$requestBuilder->setRecipientAddress(
    $recipientName = 'Jane Doe',
    $recipientCountry = 'DE',
    $recipientPostalCode = '53113',
    $recipientCity = 'Bonn',
    $recipientStreet = 'Sträßchensweg',
    $recipientStreetNumber = '2'
);
$requestBuilder->setShipmentDetails($productCode = 'V01PAK', $shipmentDate = new \DateTime());
$requestBuilder->setPackageDetails($weightInKg = 2.4);

$shipmentOrder = $requestBuilder->create();
$shipments = $service->createShipments([$shipmentOrder], $orderConfiguration);