anchor.diff:                                         Result2 == ok ->
                                              {{ok, done}, TransLog2};
                                          true ->
  -                                           {{fail, notfound}, TransLog2}
  +                                           {{fail, write}, TransLog2}
                                      end;
                                  true ->
                                      {{fail, {key_changed, ReadValue}}, TransLog1}
  
positive.code:     transaction_api:delete(Key, 2000).
  
  %% @doc atomic compare and swap
  %% @spec test_and_set(key(), value(), value()) -> {fail, Reason} | ok
  test_and_set(Key, OldValue, NewValue) ->
      TFun = fun(TransLog) ->
                     {Result, TransLog1} = transaction_api:read(Key, TransLog),
  
negative.code: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  %% @type key() = term(). Key
  -type(key() :: term()).
  %% @type value() = term(). Value
  -type(value() :: term()).
  
  process_request_list(TLog, ReqList) ->
      erlang:put(instance_id, process_dictionary:find_group(cs_node)),
  