anchor.diff:  %% Purpose: Convert process state when code is changed
   %% Returns: {ok, NewState}
   %%----------------------------------------------------------------------
  -code_change(OldVsn, State, Extra) ->
  +code_change(_OldVsn, State, _Extra) ->
       {ok, State}.
   
   %%%----------------------------------------------------------------------
  
positive.code: %%          {noreply, State, Timeout} |
  %%          {stop, Reason, State}            (terminate/2 is called)
  %%----------------------------------------------------------------------
  handle_info(Info, State) ->
      {noreply, State}.
  
  %%----------------------------------------------------------------------
  
negative.code: %%          {stop, Reason, Reply, State}   | (terminate/2 is called)
  %%          {stop, Reason, State}            (terminate/2 is called)
  %%----------------------------------------------------------------------
  handle_call(_Request, _From, State) ->
      Reply = ok,
      {reply, Reply, State}.
  
  