/**
  * Check whether specified billing address is default for its customer
  *
  * @param Address $address
  * @return bool
  */
 protected function _isDefaultBilling($address)
 {
     return $address->getId() && $address->getId() == $address->getCustomer()->getDefaultBilling() || $address->getIsPrimaryBilling() || $address->getIsDefaultBilling();
 }