anchor.diff:          windex_db:store(primary_tree, Index, NewTree).
   
   delete(Index, Rev) -> ok.
  +
  +deleteByValue(Index, Value) -> ok.
   
   export({SubTree, Data}) when is_map(SubTree)->
           #{
  
positive.code: 
  makeTree(Revision) when is_map(Revision) -> {doMakeTree(Revision), []}.
  doMakeTree(Revision) when is_map(Revision) ->
          maps:map(fun(_Key, Value) -> convertNode(Value) end, Revision).
  
  mergeTrees({LsubTree, Ldata}, {RsubTree, Rdata}) ->
          NewData = lists:umerge(Ldata, Rdata),
  
negative.code:                 {ok, LeftValue} -> mergeTrees(LeftValue, Value)
          end,
          hashMerge(maps:put(Key, NewValue, Left), Rest).
  
  compactNode(Node) when is_map(Node) ->
          maps:from_list([ {K, V} || {K, V} <- maps:to_list(Node), V =/= {#{}, []}]).
  