anchor.diff:  %% API
   -export([start_link/0,
            start_link/1,
  -         task_completed/2]).
  +         task_completed/2,
  +         is_task_completed/1]).
   
   %% gen_server callbacks
   -export([init/1,
  
positive.code:     {reply, term(), #state{}}.
  
  %% @private
  handle_call({task_completed, Task, Node}, _From, #state{eredis=Eredis}=State) ->
      Path = prefix(Task, Node),
      lager:info("Setting ~p to true.", [Path]),
  
negative.code: task_completed(Task, Node) ->
      gen_server:call(?MODULE, {task_completed, Task, Node}, infinity).
  
  %% @doc Determine if a task is completed.
  -spec is_task_completed(atom()) -> ok.
  is_task_completed(Task) ->
      gen_server:call(?MODULE, {is_task_completed, Task}, infinity).
  
  
  %%%===================================================================
  %%% gen_server callbacks
  %%%===================================================================
  