anchor.diff:              false
       end.
   
  -%% @doc Garbage collection.
  +%% @doc Garbage collection triggered by reads.
   snapshot_insert_gc(Key, SnapshotDict, OpsDict, SnapshotCache, OpsCache)-> 
   	case (orddict:size(SnapshotDict))==?SNAPSHOT_THRESHOLD of 
   	true ->
  
positive.code: 				(belongs_to_snapshot(Threshold,(lists:last(Value))#clocksi_payload.snapshot_time)) end, OpsDict).
  
  
  %% @doc Garbage collect the operations cache. 
  ops_gc(OpsDict)-> 
      OpsDict.
      
      
      
  
negative.code: 		case orddict:filter(fun(Key, _Value) -> 
  				belongs_to_snapshot(Key, SnapshotTime) end, [H|T]) of 
  			[]->
  		        {ok,no_snapshot};
  		    [H1|T1]->
  				{CommitTime, Snapshot} = lists:last([H1|T1]),
  				{ok, {CommitTime, Snapshot}}
  