anchor.diff:  
   %% @doc The append/2 function adds an operation to the log of the CRDT
   %%      object stored at some key.
  --spec append(key(), type(), {op(),term()}) -> 
  +-spec append(key(), type(), {op(),term()}) ->
                       {ok, {txid(), [], snapshot_time()}} | {error, term()}.
   append(Key, Type, {OpParams, Actor}) ->
       case materializer:check_operations([{update,
  
positive.code:             gr_snapshot_read(ClientClock, Args)
      end.
  -endif.
       
  
negative.code: 
  
  %% Clock SI API
  %% TODO: Move these functions into clocksi files. Public interface should only
  %%       contain generic transaction interface
  
  %% @doc Starts a new ClockSI transaction.
  