code: def delete_topology_entry(self, **req):
          
          session = db.get_session()
          with session.begin(subtransactions=True):
              try:
                  rows = session.query(DfaTopologyDb).filter_by(**req).all()
              except orm_exc.NoResultFound:
                  LOG.info("No Topology results found for %s", req)
                  return
              try:
                  for row in rows:
                      session.delete(row)
              except Exception as exc:
                  LOG.error("Exception raised %s", str(exc))
docs: Delete the entries from the topology DB.