anchor.diff:  init([Source, Level]) ->
       init([Source, Level, {lager_default_formatter, ?DEFAULT_FORMAT}]);
   init([Source, Level, {Formatter, FormatterConfig}]) ->
  -    case nt_eventlog:register_event_source(Source) of
  -        {ok, Handle} ->
  -            {ok, #state{id = {?MODULE, Source},
  -                        level=lager_util:level_to_num(Level),
  -                        handle = Handle,
  -                        formatter = Formatter,
  -                        format_config = FormatterConfig}};
  +    case parse_level(Level) of
  +        {ok, Lvl} ->
  +            case nt_eventlog:register_event_source(Source) of
  +                {ok, Handle} ->
  +                    {ok, #state{id = {?MODULE, Source},
  +                                level = Lvl,
  +                                handle = Handle,
  +                                formatter = Formatter,
  +                                format_config = FormatterConfig}};
  +                Error ->
  +                    Error
  +            end;
           Error ->
               Error
       end.
  
positive.code:     {ok, State}.
  
  config_to_id([Source | _]) ->
      {?MODULE, Source}.
negative.code: handle_call(get_loglevel, #state{level=Level} = State) ->
      {ok, Level, State};
  handle_call({set_loglevel, Level}, State) ->
      case parse_level(Level) of
          {ok, Lvl} ->
              {ok, ok, State#state{level = Lvl}};
          Error ->
              {ok, Error, State}
      end;
  handle_call(_Request, State) ->
      {ok, ok, State}.
  
  