anchor.diff:      is_subtype(Status,      db_generator:db_status()).
   start_sync(Config, NodeCount, DBSize, DBParams, Rounds, Fpr, RRConfig) ->
       NodeKeys = lists:sort(get_symmetric_keys(NodeCount)),
  -    %build and fill ring
       build_symmetric_ring(NodeCount, Config, RRConfig),
       config:write(rr_bloom_fpr, Fpr),
  -    %fill_symmetric_ring(DataCount, NodeCount, OutdatedProb),
       erlang:put(?DBSizeKey, ?REP_FACTOR * DBSize),
       db_generator:fill_ring(random, DBSize, DBParams),
  -    %measure initial sync degree
       InitDBStat = get_db_status(),
       print_status(0, InitDBStat),
  -    %run sync rounds
       util:for_to_ex(1, Rounds, 
                      fun(I) ->
                              startSyncRound(NodeKeys),
  
positive.code:                            print_status(I, get_db_status())
                     end),
      EndStat = get_db_status(),
      %clean up
      unittest_helper:stop_ring(),
      {InitDBStat, EndStat}.
  
  
negative.code:                              intervals:in(Key, intervals:new(LBr, LK, RK, RBr)) 
                       end, RingData),
      case N of
          [{_Pid, _I, DB, _Pred, _Succ, ok}] -> length(DB);
          _ -> 0
      end.
  