anchor.diff:  %% userdevguide-begin rt_frtchord:check
   %% @doc Notifies the dht_node and failure detector if the routing table changed.
   %%      Provided for convenience (see check/5).
  --spec check(OldRT::rt(), NewRT::rt(), Neighbors::nodelist:neighborhood(),
  -            ReportToFD::boolean()) -> ok.
   check(OldRT, NewRT, Neighbors, ReportToFD) ->
       check(OldRT, NewRT, Neighbors, Neighbors, ReportToFD).
   
  
positive.code: %%      Also updates the failure detector if ReportToFD is set.
  %%      Note: the external routing table only changes if the internal RT has
  %%      changed.
  -spec check(OldRT::rt(), NewRT::rt(), OldNeighbors::nodelist:neighborhood(),
              NewNeighbors::nodelist:neighborhood(), ReportToFD::boolean()) -> ok.
  check(OldRT, OldRT, _, _, _) -> ok;
  check(OldRT, NewRT, _OldNeighbors, NewNeighbors, ReportToFD) ->
      Pid = pid_groups:get_my(dht_node),
  
negative.code: 
  %% userdevguide-begin rt_frtchord:get_random_node_id
  %% @doc Generates a random node id, i.e. a random 128-bit number.
  get_random_node_id() ->
      case config:read(key_creator) of
          random -> hash_key_(randoms:getRandomString());
  