code: def make_route_refresh_request(self, peer_ip, *route_families):
          
          LOG.debug('Route refresh requested for peer %s and route families %s',
                    peer_ip, route_families)
          if not SUPPORTED_GLOBAL_RF.intersection(route_families):
              raise ValueError('Given route family(s) % is not supported.' %
                               route_families)
  
          peer_list = []
          # If route-refresh is requested for all peers.
          if peer_ip == 'all':
              peer_list.extend(self.get_peers_in_established())
          else:
              given_peer = self._peers.get(peer_ip)
              if not given_peer:
                  raise ValueError('Invalid/unrecognized peer %s' % peer_ip)
              if not given_peer.in_established:
                  raise ValueError('Peer currently do not have established'
                                   ' session.')
              peer_list.append(given_peer)
  
          # Make route refresh request to valid peers.
          for peer in peer_list:
              peer.request_route_refresh(*route_families)
  
          return True
docs: Request route-refresh for peer with `peer_ip` for given
          `route_families`.
  
          Will make route-refresh request for a given `route_family` only if such
          capability is supported and if peer is in ESTABLISHED state. Else, such
          requests are ignored. Raises appropriate error in other cases. If
          `peer_ip` is equal to 'all' makes refresh request to all valid peers.