anchor.diff:  % where rnd is chosen uniformly from [0,1)
   handle_custom_message({trigger_random_lookup}, State) ->
       RT = rt_loop:get_rt(State),
  -    SourceNode = ?RT:get_source_node(RT),
  +    SourceNode = get_source_node(RT),
       SourceNodeId = entry_nodeid(SourceNode),
       {PredId, SuccId} = adjacent_fingers(SourceNode),
       Key = get_random_key_from_generator(SourceNodeId, PredId, SuccId),
  
positive.code: 
  %% userdevguide-begin rt_frtchord:export_rt_to_dht_node
  %% @doc Converts the internal RT to the external RT used by the dht_node.
  %% The external routing table is optimized to speed up ?RT:next_hop/2. For this, it is
  %%  only a gb_tree with keys being node ids and values being of type node:node_type().
  -spec export_rt_to_dht_node_helper(rt()) -> external_rt().
  export_rt_to_dht_node_helper(RT) ->
  
negative.code: 
          false -> OldRT
      end,
      check(OldRT, NewRT, rt_loop:get_neighb(State), true),
      rt_loop:set_rt(State, NewRT);
  
  % lookup a random key chosen with a pdf:
  