anchor.diff:          -> NewNode::mt_node().
   insert_to_node(Key, _CheckKey, {_H, Count, LeafCount = 1, Bucket, Interval, []} = N, Config)
     when Count >= 0 andalso Count < Config#mt_config.bucket_size ->
  -    case lists:member(Key, Bucket) of
  +    case lists:keymember(element(1, Key), 1, Bucket) of
           false -> {nil, Count + 1, LeafCount, [Key | Bucket], Interval, []};
           _     -> N
       end;
  
positive.code: %%      e.g. [{branch_factor, 32}, {bucket_size, 16}]
  -spec new(mt_interval(), mt_config_params()) -> merkle_tree().
  new(I, ConfParams) ->
      Config = build_config(ConfParams),
      [Root] = build_childs([{I, 0, []}], Config, []),
      gen_hash({merkle_tree, Config, Root}).
  
  %% @doc Creates a new empty merkle tree with the given params and interval and
  %%      inserts entries from EntryList.
  
negative.code: gen_hash_node({_OldHash, Count, _LCnt, Bucket, Interval, [] = Childs},
                _InnerHf, LeafHf, true, CleanBuckets) ->
      % leaf node, no bucket contents, keep_bucket true
      Bucket1 = lists:keysort(1, Bucket),
      Hash = run_leaf_hf(Bucket1, Interval, LeafHf),
      {Hash, Count, 1, ?IIF(CleanBuckets, [], Bucket1), Interval, Childs}.
  
  