anchor.diff:  validate_histogram_bound(Bound) ->
     erlang:error({histogram_invalid_bound, Bound}).
   
  -
   dobserve_impl(Registry, Name, LabelValues, Value) ->
     case ets:lookup(?TABLE, {Registry, Name, LabelValues}) of
       [Metric]->
  
positive.code: %%====================================================================
  %% Private Parts
  %%====================================================================
  validate_histogram_bounds([]) ->
    erlang:error({histogram_no_bounds, []});
  validate_histogram_bounds(undefined) ->
  
negative.code:   register(Registry),
    prometheus_metric:insert_mf(?TABLE, Registry, Name, Labels, Help, Bounds).
  
  observe(Name, Value) ->
    observe(default, Name, [], Value).
  
  