anchor.diff:  unregister(Name) ->
       gproc:unreg({n, l, Name}).
   
  +%% @doc Unregister the local process as a member of a group
  +%% @end
  +-spec unregister_member(tuple()) -> true.
  +unregister_member(Group) ->
  +    gproc:unreg({p, l, Group}).
  +
   
   %% @doc Resolve a local name to a pid
   %% @end
   -spec lookup(tuple()) -> pid().
   lookup(Name) ->
       gproc:lookup_pid({n, l, Name}).
  +
  +%% @doc Lookup the process id's of all members of a group
  +%% @end
  +-spec lookup_members(tuple()) -> [pid()].
  +lookup_members(Group) ->
  +    gproc:lookup_pids({p, l, Group}).
   
   
   %% @doc Wait until a process registers under a local name
  
positive.code:     {setup,
          fun() -> application:start(gproc) end,
          fun(_) -> application:stop(gproc) end,
      ?_test(begin
          true = ?utils:register(name),
          ?assertEqual(self(), ?utils:lookup(name)),
          ?assertEqual(self(), ?utils:await(name))
      end)}.
  
  -ifdef(PROPER).
  
  
negative.code: 
  %% "registry-like" functions
  -export([register/1,
           register_member/1,
           unregister/1,
           unregister_member/1,
           lookup/1,
           lookup_members/1,
           await/1]).
  
  %%====================================================================
  