code: def propogate_candidates(self, node_ip):
          
  
          if node_ip in self.factory.candidates:
              old_candidates = []
              for candidate in self.factory.candidates[node_ip]:
                  # Not connected.
                  if not candidate["con"].connected:
                      continue
  
                  # Already sent -- updated when they accept this challenge.
                  if candidate["propogated"]:
                      continue
  
                  # Notify node of challege from client.
                  msg = "CHALLENGE %s %s %s" % (
                      candidate["ip_addr"],
                      " ".join(map(str, candidate["predictions"])),
                      candidate["proto"])
  
                  self.factory.nodes["simultaneous"][node_ip]["con"].\
                      send_line(msg)
                  old_candidates.append(candidate)
docs: Used to progate new candidates to passive simultaneous
          nodes.