code: def _add(self, hostport):
          
          peer = self.peer_class(
              tchannel=self.tchannel,
              hostport=hostport,
              on_conn_change=self._update_heap,
          )
          peer.rank = self.rank_calculator.get_rank(peer)
          self._peers[peer.hostport] = peer
  
          self.peer_heap.add_and_shuffle(peer)
docs: Creates a peer from the hostport and adds it to the peer heap