code: def register_peer(self, connection_id, endpoint):
          
          with self._lock:
              if len(self._peers) < self._maximum_peer_connectivity:
                  self._peers[connection_id] = endpoint
                  self._topology.set_connection_status(connection_id,
                                                       PeerStatus.PEER)
                  LOGGER.debug("Added connection_id %s with endpoint %s, "
                               "connected identities are now %s",
                               connection_id, endpoint, self._peers)
              else:
                  raise PeeringException(
                      "At maximum configured number of peers: {} "
                      "Rejecting peering request from {}.".format(
                          self._maximum_peer_connectivity,
                          endpoint))
  
          public_key = self.peer_to_public_key(connection_id)
          if public_key:
              self._consensus_notifier.notify_peer_connected(public_key)
docs: Registers a connected connection_id.
  
          Args:
              connection_id (str): A unique identifier which identifies an
                  connection on the network server socket.
              endpoint (str): The publically reachable endpoint of the new
                  peer