anchor.diff:  %%      Used to subscribe to the ring maintenance for {slide_finished, succ} or
   %%      {slide_finished, pred} msg.
   -spec rm_send_activation_msg(Subscriber, ?MODULE, Neighbours, Neighbours) -> ok when
  -                             Subscriber :: pid(),
  -                             Neighbours::nodelist:neighborhood().
  +                             is_subtype(Subscriber, pid()),
  +                             is_subtype(Neighbours, nodelist:neighborhood()).
   rm_send_activation_msg(_Pid, ?MODULE, _OldNeighbours, NewNeighbours) ->
       %% io:format("Pid: ~w. Self: ~w. PidGossip: ~w~n", [Pid, self(), Pid2]),
       MyRange = nodelist:node_range(NewNeighbours),
  
positive.code: %% @doc Checks whether the received notification is a {slide_finished, succ} or
  %%      {slide_finished, pred} msg. Used as filter function for the ring maintanance.
  -spec rm_filter_slide_msg(Neighbors, Neighbors, Reason) -> boolean() when
                            Neighbors :: nodelist:neighborhood(),
                            Reason :: rm_loop:reason().
  rm_filter_slide_msg(_OldNeighbors, _NewNeighbors, Reason) ->
          Reason =:= {slide_finished, pred} orelse Reason =:= {slide_finished, succ}.
  
  
negative.code: 
  -spec tester_create_state(Status, Range, Interval,
      CBState, CBStatus, ExchData, Round, TriggerLock, Cycles) -> state()
      when    is_subtype(Status, init | uninit),
              is_subtype(Range, intervals:interval()),
              is_subtype(Interval, pos_integer()),
              is_subtype(CBState, any()),
              is_subtype(CBStatus, unstarted | started | tombstone),
              is_subtype(ExchData, any()),
              is_subtype(Round, non_neg_integer()),
              is_subtype(TriggerLock, free | locked),
              is_subtype(Cycles, non_neg_integer()).
  tester_create_state(Status, Range, Interval, CBState, CBStatus,
          ExchData, Round, TriggerLock, Cycles) ->
      State = ?PDB:new(state, ?PDB_OPTIONS),
  