/**
  * @param Payone_Core_Model_Domain_Config_PaymentMethod $child
  * @param Payone_Core_Model_Domain_Config_PaymentMethod $parent
  * @return Payone_Core_Model_Domain_Config_PaymentMethod
  */
 protected function mergeData(Payone_Core_Model_Domain_Config_PaymentMethod $child, Payone_Core_Model_Domain_Config_PaymentMethod $parent)
 {
     foreach ($child->getData() as $key => $value) {
         if ($value === null || $value === false) {
             $child->setData($key, $parent->getData($key));
         }
     }
     return $child;
 }