anchor.diff:  %%
   %% -------------------------------------------------------------------- %%
   
  -handle_cast(stop, State) ->
  -    {stop, normal, State};
   handle_cast(_, State) ->
       {noreply, State}.
   
  
positive.code: 	    {reply, {error, Error}, State}
      end;
  
  
  handle_call(Command, _From, State) ->
      {reply, {error, {undefined, Command}}, State}.
  
negative.code: %% -------------------------------------------------------------------- %%
  
  start()  -> gen_server:start({local, ?MODULE}, ?MODULE, [], []).
  stop()   -> gen_server:call(?MODULE, stop, infinity).
  init([]) -> {ok, #state{ locks = [], duration = 0 } }.
  
  %% -------------------------------------------------------------------- %%
  