anchor.diff:                end,
       %% see HINT in foldl/5
       %% now retrieve actual data
  -    lists:foldl(fun(Key, AccIn) ->
  -                        Entry = toke_drv:get(DB, ?IN(Key)),
  -                        Fun(?OUT(Entry), AccIn)
  -                end, Acc, CutData).
  +    lists:foldl(Fun, Acc, CutData).
   
   %% @private get_all_keys/3 retrieves all keys in DB that fall into Interval but
   %%          not more than MaxNum. If MaxNum == -1 all Keys are retrieved. If
  
positive.code: 
  %% @doc Equivalent to toke_drv:fold(Fun, Acc0, DB).
  %%      Returns a potentially larger-than-memory dataset. Use with care.
  -spec foldl(DB::db(), Fun::fun((entry(), AccIn::A) -> AccOut::A), Acc0::A) -> Acc1::A.
  foldl(State, Fun, Acc) ->
      foldl_helper(State, Fun, Acc, all, -1).
  
  %% @equiv foldl(DB, Fun, Acc0, Interval, get_load(DB))
  %% @doc   Returns a potentially larger-than-memory dataset. Use with care.
  -spec foldl(DB::db(), Fun::fun((entry(), AccIn::A) -> AccOut::A), Acc0::A,
                                 Interval::db_backend_beh:interval()) -> Acc1::A.
  foldl(State, Fun, Acc, Interval) ->
      foldl_helper(State, Fun, Acc, Interval, -1).
  
negative.code: %%      encountered in Interval. On the first call AccIn == Acc0. The iteration
  %%      stops as soon as MaxNum elements have been encountered.
  %%      Returns a potentially larger-than-memory dataset. Use with care.
  -spec foldl(DB::db(), Fun::fun((Key::key(), AccIn::A) -> AccOut::A), Acc0::A,
                                 Intervall::db_backend_beh:interval(), MaxNum::non_neg_integer()) -> Acc1::A.
  foldl(State, Fun, Acc, Interval, MaxNum) ->
      %% HINT
  