code: def peer_exchange(self, peer_host, peer_port):
          
          # get peers
          peer_list = atlas_get_live_neighbors( "%s:%s" % (peer_host, peer_port) )
          if len(peer_list) > atlas_max_neighbors():
              random.shuffle(peer_list)
              peer_list = peer_list[:atlas_max_neighbors()]
  
          log.info("Enqueue remote peer {}:{}".format(peer_host, peer_port))
          atlas_peer_enqueue( "%s:%s" % (peer_host, peer_port))
  
          log.debug("Live peers reply to %s:%s: %s" % (peer_host, peer_port, peer_list))
          return peer_list
docs: Exchange peers.
          Add the given peer to the list of new peers to consider.
          Return the list of healthy peers