anchor.diff:                        NextKey, {?send_to_group_member, routing_table, Msg});
                   _ -> ok
               end,
  -            NewRT;
  -        _ -> RT
  +            Changed = (Index =:= first_index() orelse
  +                          (gb_trees:lookup(prev_index(Index), RT) =/= {value, Node})),
  +            {gb_trees:enter(Index, Node, RT), Changed};
  +        _ ->
  +            {RT, false}
       end.
   %% userdevguide-end rt_chord:stabilize
   
  
positive.code: next_index({I, J}) ->
      {I, J - 1}.
  
  %% @doc Checks whether config parameters of the rt_chord process exist and are
  %%      valid.
  -spec check_config() -> boolean().
  
negative.code: 
  %% userdevguide-begin rt_chord:stabilize
  %% @doc Updates one entry in the routing table and triggers the next update.
  %%      Changed indicates whether a new node was inserted (the RT structure may
  %%      change independently from this indicator!).
  -spec stabilize(Neighbors::nodelist:neighborhood(), OldRT::rt(), Index::index(),
                  Node::node:node_type()) -> {NewRT::rt(), Changed::boolean()}.
  stabilize(Neighbors, RT, Index, Node) ->
      MyId = nodelist:nodeid(Neighbors),
      Succ = nodelist:succ(Neighbors),
  