anchor.diff:      end.
   
   %% @doc reads the value of a key
  -%% @spec read(key()) -> {failure, term()} | value()
  +%% @spec read(key()) -> value() | {fail, term()} 
  +-spec read(key()) -> value() | {fail, term()}.
   read(Key) ->
       case util:tc(transaction_api, quorum_read, [Key]) of
           {_Time, {fail, Reason}} ->
  
positive.code:                                        Result2 == ok ->
                                             {{ok, done}, TransLog2};
                                         true ->
                                             {{fail, notfound}, TransLog2}
                                     end;
                                 true ->
                                     {{fail, {key_changed, ReadValue}}, TransLog1}
  
negative.code: 
  %% @doc writes the value of a key
  %% @spec write(key(), value()) -> ok | {fail, term()}
  -spec write(key(), value()) -> ok | {fail, term()}.
  write(Key, Value) ->
      case util:tc(transaction_api, single_write, [Key, Value]) of
          {_Time, commit} ->
  