anchor.diff:  %%      valid.
   -spec check_config() -> boolean().
   check_config() ->
  -    config:cfg_is_integer(rrd_timing_hist_size) and
  +    config:cfg_is_integer(rrd_timing_hist_size) andalso
       config:cfg_is_greater_than_equal(rrd_timing_hist_size, 0).
   
   -spec get_timing_hist_size() -> non_neg_integer().
  
positive.code: event_update_fun(Time, undefined, New) -> [{Time, New}];
  event_update_fun(Time, Old, New) -> lists:append(Old, [{Time, New}]).
  
  -spec timing_update_fun(Time::internal_time(), Old::timing_type() | undefined, New::number())
          -> timing_type().
  timing_update_fun(_Time, undefined, New) ->
  
negative.code:         gauge -> fun gauge_update_fun/3;
          counter -> fun counter_update_fun/3;
          event -> fun event_update_fun/3;
          {histogram, Size} -> fun(One, Two, Three) -> histogram_update_fun(One, Two, Three, Size) end;
          {histogram, Size, NormFun, InverseFun} -> fun(One, Two, Three) -> histogram_normalized_update_fun(One, Two, Three, Size, NormFun, InverseFun) end;
          {timing, _} -> fun timing_update_fun/3;
          {timing_with_hist, _} -> fun timing_with_hist_update_fun/3
      end.
  