anchor.diff:  
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  -% @doc Returns an iterator to visit all tree nodes with next
  +% @doc Returns an iterator to visit all tree nodes with next/1.
   %      Iterates over all tree nodes from left to right in a deep first manner.
   -spec iterator(Tree::merkle_tree()) -> Iter::mt_iter().
   iterator({merkle_tree, _, Root}) -> [Root].
  
positive.code: -spec insert_to_node(Key::mt_bucket_entry(), CheckKey::?RT:key(),
                       Node::mt_node(), Config::mt_config())
          -> NewNode::mt_node().
  insert_to_node(Key, _CheckKey, {_H, Count, LeafCount, Bucket, Interval, []} = N, Config)
    when Count >= 0 andalso Count < Config#mt_config.bucket_size ->
      case lists:member(Key, Bucket) of
          false -> {nil, Count + 1, LeafCount, [Key | Bucket], Interval, []};
          _     -> N
      end;
  
  insert_to_node(Key, CheckKey, {_, BucketSize, LeafCount, Bucket, Interval, []},
                 #mt_config{ branch_factor = BranchFactor,
                             bucket_size = BucketSize } = Config) ->
      % former leaf node which will become an inner node
      ChildI = intervals:split(Interval, BranchFactor),
      NewLeafs = [{nil, CX, -1, BX, IX, []}
                 || {IX, CX, BX} <- keys_to_intervals(Bucket, ChildI)],
      insert_to_node(Key, CheckKey, {nil, 1 + BranchFactor, LeafCount, [], Interval, NewLeafs}, Config);
  
  insert_to_node(Key, CheckKey, {Hash, Count, LeafCount, [], Interval, Childs = [_|_]} = Node, Config) ->
      {Dest0, Rest} = lists:partition(fun({_H, _Cnt, _LCnt, _Bkt, I, _CL}) ->
  
negative.code:         [] -> error_logger:error_msg("InsertFailed!"), Node;
          [Dest|_] ->
              OldSize = node_size(Dest),
              OldLC = get_leaf_count(Dest),
              NewDest = insert_to_node(Key, CheckKey, Dest, Config),
              {Hash, Count - OldSize + node_size(NewDest),
               LeafCount - OldLC + get_leaf_count(NewDest), [], Interval, [NewDest|Rest]}
      end.
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  