anchor.diff:  
   handle_cast(nodes_wanted_updated, State) ->
       self() ! notify_clients,
  -    do_nodes_wanted_updated(do_nodes_wanted()),
  +    do_nodes_wanted_updated(nodes_wanted()),
       {noreply, State};
   
   handle_cast(we_were_shunned, #state{we_were_shunned = true} = State) ->
  
positive.code: 
  nodes_actual_proper() ->
      Curr = nodes_actual(),
      Want = do_nodes_wanted(),
      Diff = lists:subtract(Curr, Want),
      lists:usort(lists:subtract(Curr, Diff)).
  
  
negative.code:     lists:subtract(nodes_actual_proper(), [node()]).
  
  nodes_wanted() ->
      nodes_wanted('latest-config-marker').
  
  nodes_wanted(Config) ->
      lists:usort(ns_config:search(Config, nodes_wanted, [])).
  
  % API's used as callbacks that are invoked when ns_config
  % keys have changed.
  