/**
  * Extracts tracking informations from the passed shipment object.
  *
  * @param  EbayEnterprise_Order_Model_Detail_Process_Response_Shipment
  * @return array
  */
 protected function extractTrackingDataFromShipment(EbayEnterprise_Order_Model_Detail_Process_Response_Shipment $shipment)
 {
     /** @var array */
     $trackingData = [];
     /** @var array */
     $tracks = $shipment->getTracks();
     foreach ($tracks as $track) {
         if ($this->trackingNumber && $this->trackingNumber === $track) {
             return [$this->getTrack($shipment, $track)];
         } else {
             $trackingData[] = $this->getTrack($shipment, $track);
         }
     }
     return $trackingData;
 }