anchor.diff:  
   increment_domain(Mod, Domain, Key, Count) ->
       ets:update_counter(?MODULE, {Mod, Domain, Key}, Count).
  +
  +
  +
  +%% @doc Sets a config value.
  +-spec update_domain(term(), nklib:domain(), term(), fun((term()) -> term())) ->
  +    ok.
  +
  +update_domain(Mod, Domain, Key, Fun) ->
  +    gen_server:call(?MODULE, {update, Mod, Domain, Key, Fun}).
   
   
   %% @doc Loads parsed application environment
  
positive.code: -spec handle_call(term(), {pid(), term()}, #state{}) ->
      {noreply, #state{}}.
  
  handle_call(Msg, _From, State) -> 
      lager:error("Module ~p received unexpected call ~p", [?MODULE, Msg]),
      {noreply, State}.
  
  
negative.code:     increment_domain(Mod, none, Key, Count).
  
  
  %% @doc Sets a config value.
  -spec update(term(), term(), fun((term()) -> term())) ->
      ok.
  
  update(Mod, Key, Fun) ->
      update_domain(Mod, none, Key, Fun).
  
  
  
  %% @private
  -spec get_domain(term(), nklib:domain(), term()) -> 
      Value :: term().
  