anchor.diff:  
   -export([start_link/0,
            push_nci/0,
  -         clean_data/0]).
  +         clean_data/0,
  +         caller/1]).
   
   -export([init/1,
            handle_call/3,
  
positive.code: clean_data() ->
      gen_server:cast(?MODULE, clean_data).
  
  %------------------------------------------------------------------------------
  % gen_server callbacks
  %------------------------------------------------------------------------------
  
negative.code: 
  handle_cast(start, State) ->
      DataMaxAge = data_max_age(),
      {ok, NCITimer} = interval_timer(fun nci_min_interval/0, fun push_nci/0),
      {ok, CleanTimer} = interval_timer(fun clean_interval/0, fun clean_data/0),
      {noreply, State#?STATE{nci_update_timer = NCITimer,
                             clean_timer = CleanTimer,
                             data_max_age = DataMaxAge}};
  