anchor.diff:  %%      If the value stored at Key is the same as OldValue, then NewValue will
   %%      be stored.
   -spec test_and_set(Key::client_key(), OldValue::client_value(), NewValue::client_value())
  -        -> testandset_result().
  +        -> testandset_result() | {fail, abort}.
   test_and_set(Key, OldValue, NewValue) ->
       ReqList = [{test_and_set, Key, OldValue, NewValue}, {commit}],
       {_TLog, [Res1, Res2]} = req_list(tx_tlog:empty(), ReqList),
  
positive.code: 
  %% @doc Atomically perform a set_change operation and a commit (not as part of a transaction).
  -spec set_change(client_key(), ToAdd::[client_value()], ToRemove::[client_value()])
             -> listop_result().
  set_change(Key, ToAdd, ToRemove) ->
      ReqList = [{set_change, Key, ToAdd, ToRemove}, {commit}],
      {_TLog, [Res1, Res2]} = req_list(tx_tlog:empty(), ReqList),
  
negative.code: 
  %% @doc Atomically perform a set_change operation and a commit (not as part of a transaction).
  -spec number_add(client_key(), ToAdd::number())
             -> numberop_result() | {fail, abort}.
  number_add(Key, ToAdd) ->
      ReqList = [{number_add, Key, ToAdd}, {commit}],
      {_TLog, [Res1, Res2]} = req_list(tx_tlog:empty(), ReqList),
  