code: def create_locks(context, network_ids, addresses):
      
  
      for address in addresses:
          address_model = None
          try:
              address_model = _find_or_create_address(
                  context, network_ids, address)
              lock_holder = None
              if address_model.lock_id:
                  lock_holder = db_api.lock_holder_find(
                      context,
                      lock_id=address_model.lock_id, name=LOCK_NAME,
                      scope=db_api.ONE)
  
              if not lock_holder:
                  LOG.info("Creating lock holder on IPAddress %s with id %s",
                           address_model.address_readable,
                           address_model.id)
                  db_api.lock_holder_create(
                      context, address_model, name=LOCK_NAME, type="ip_address")
          except Exception:
              LOG.exception("Failed to create lock holder on IPAddress %s",
                            address_model)
              continue
      context.session.flush()
docs: Creates locks for each IP address that is null-routed.
  
      The function creates the IP address if it is not present in the database.