anchor.diff:                  SessionId, {guid, FileId}, Key
               )
           end, XattrKeys),
  -    ok = logical_file_manager:set_metadata(
  -        SessionId, {guid, FileId}, <<"json">>, #{}, []
  -    ),
  -    ok = logical_file_manager:set_metadata(
  -        SessionId, {guid, FileId}, <<"rdf">>, undefined, []
  +    ok = logical_file_manager:remove_metadata(
  +        SessionId, {guid, FileId}, json
  +    ),
  +    ok = logical_file_manager:remove_metadata(
  +        SessionId, {guid, FileId}, rdf
       ),
       ok.
   
  
positive.code:         JSON ->
              JSONMap = json_utils:decode_map(json_utils:encode(JSON)),
              ok = logical_file_manager:set_metadata(
                  SessionId, {guid, FileId}, <<"json">>, JSONMap, []
              )
      end,
      case proplists:get_value(<<"rdf">>, Data) of
  
negative.code:         _ -> Basic
      end,
      {ok, JSON} = logical_file_manager:get_metadata(
          SessionId, {guid, FileId}, json, [], false
      ),
      JSONVal = case JSON of
          ?ENOATTR -> null;
          _ -> json_utils:decode(json_utils:encode_map(JSON))
      end,
      {ok, RDF} = logical_file_manager:get_metadata(
          SessionId, {guid, FileId}, rdf, [], false
      ),
      RDFVal = case RDF of
          ?ENOATTR -> null;
          _ -> RDF
      end,
      {ok, [
  