anchor.diff:  %% handle_call
   %% ------------------------------------------------------------------
   
  +%% @hidden
   handle_call({authentication, Username, Password}, undefined) ->
   	% TODO mnesia backed
   	{reply, undefined, undefined};
  
positive.code: %% code_change
  %% ------------------------------------------------------------------
  
  code_change(_Oldvsn, State, _Extra) ->
  	{ok, State}.
  
  
negative.code: %% format_status
  %% ------------------------------------------------------------------
  
  %% @hidden
  format_status(Opt, [PDict, State]) ->
  	[{data, [{"State", State}]}].
  
  