anchor.diff:              Err
       end.
   
  -delete(TokenId) when is_binary(TokenId) ->
  +destroy(TokenId) when is_binary(TokenId) ->
       case lookup(TokenId) of
           #token{} ->
               redis_helper:delete_token(TokenId);
  
positive.code: new_unique_token_id(Retries) when is_integer(Retries),
                                    Retries > 0 ->
      TokenId = new_token_id(),
      case ets:lookup(tokens, TokenId) of
          [#token{}] -> new_unique_token_id(Retries-1);
          [] -> TokenId
      end.
  
negative.code:     iolist_to_binary(["t.", uuid:to_iolist(uuid:v4())]).
  
  lookup_by_channel(ChannelId) when is_integer(ChannelId) ->
      Ids = [ Id
              || #token_idx{id = Id} <- ets:lookup(?CHAN_TOKEN_TAB, ChannelId)],
      lists:flatmap(fun (Id) ->
                            ets:lookup(?TOKEN_TAB, Id)
                    end,
                    Ids).
  
  store(#token{id=Token,
               channel_id=ChannelId,
  