anchor.diff:  
   read_metric_initial_value({Metric, _} = MetricSpec, Acc) ->
       Type = metric_type(Metric),
  +    maybe_reset_metric(Metric, Type),
       Value = get_value(Metric, Type),
       [{MetricSpec, Type, Value} | Acc];
   read_metric_initial_value({Precond, Metric, Change}, Acc) ->
  
positive.code: post_story_check_counters(CountersToCheck) ->
      After = [{MetricSpec, OldValue, get_value(Metric, Type)} || {{Metric, _} = MetricSpec, Type, OldValue } <- CountersToCheck],
      [] = lists:foldl(fun check_metric_change/2, [], After),
      ok.
  
  get_value(Metric, spiral) ->
  
negative.code:     lists:foldl(fun({_, [{count, X}, _]}, Sum) ->
          Sum + X
      end, 0, Values);
  get_value(Metric, histogram) ->
      get_value(Metric);
  get_value(Metric, _) ->
      get_value(Metric).
  
  