protected MaintenanceLock verifyAllLocksFromThisDocument(
     List<MaintenanceLock> maintenanceLocks, String documentNumber) {
   for (MaintenanceLock maintenanceLock : maintenanceLocks) {
     String lockingDocNumber =
         maintenanceDocumentDao.getLockingDocumentNumber(
             maintenanceLock.getLockingRepresentation(), documentNumber);
     if (StringUtils.isNotBlank(lockingDocNumber)) {
       return maintenanceLock;
     }
   }
   return null;
 }