anchor.diff:              gb_trees:enter(PredId, NewPred,
                   gb_trees:enter(SuccId, NewSucc, Tree))
       end,
  -    Ns = gb_trees:values(UpdatedTree),
  -
  -    %% TODO DELETE ASSERT
  -    Adjs = [tuple_to_list(adjacent_fingers(N)) || N <- Ns],
  -    Ids = lists:flatten(Adjs),
  -    false = lists:any(fun (none) -> true; (_) -> false end, [gb_trees:lookup(N,
  -                UpdatedTree) || N <- Ids]),
  +
       RT#rt_t{nodes=UpdatedTree}.
   
   % @doc Create an rt_entry and return the entry together with the Pred und Succ node, where
  
positive.code: %% @doc Creates an "empty" routing table.
  -spec empty(nodelist:neighborhood()) -> rt().
  empty(Neighbors) ->
      add_source_entry(nodelist:node(Neighbors), #rt_t{})
      .
  %% userdevguide-end rt_frtchord:empty
  
  
negative.code:     .
  
  % @doc Delete an entry from the routing table
  -spec entry_delete(EntryKey :: key(), RT :: rt()) -> RefinedRT :: rt().
  entry_delete(EntryKey, RT) ->
      Tree = gb_trees:delete(EntryKey, get_rt_tree(RT)),
  