anchor.diff:  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
   %%%===================================================================
  
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: %% API
  -export([start_link/0,
           start_link/1,
           task_completed/2,
           is_task_completed/1]).
  
  %% gen_server callbacks
  -export([init/1,
  