anchor.diff:  %%%
   %%% @spec add_task(binary()) -> term()
   %%% @end
  --spec add_task(binary(), schedule(), term()) -> term().
  +-spec add_task(binary(), schedule(), detail()) -> term().
   add_task(Task, Schedule, Detail) -> gen_server:call(?SERVER, {add, Task, Schedule, Detail}).
   
   %%% @doc
  
positive.code:          cancel_task/1,
           show_schedule/1,
           show_schedules/0,
           members/0
          ]).
  
  %% gen_server callbacks
  
negative.code: 
  -define(SERVER, ?MODULE).
  
  -record(state, {
            nodes = [{node(), alive}] :: [{node(), term()}]
           }).
  
  %% TODO: specifies the proprietary schedule time format.
  -type schedule() :: term().
  -type detail() :: binary().
  
  %%%===================================================================
  %%% API
  