/**
  * Parent transaction getter
  * May attempt to load it.
  *
  * @param bool $shouldLoad
  * @return Mage_Sales_Model_Order_Payment_Transaction|false
  */
 public function getParentTransaction($shouldLoad = true)
 {
     if (null === $this->_parentTransaction) {
         $this->_verifyThisTransactionExists();
         $this->_parentTransaction = false;
         $parentId = $this->getParentId();
         if ($parentId) {
             $class = get_class($this);
             $this->_parentTransaction = new $class();
             if ($shouldLoad) {
                 $this->_parentTransaction->load($parentId);
                 if (!$this->_parentTransaction->getId()) {
                     $this->_parentTransaction = false;
                 } else {
                     $this->_parentTransaction->hasChildTransaction(true)->setOrderPaymentObject($this->_paymentObject);
                 }
             }
         }
     }
     return $this->_parentTransaction;
 }