public override HistoryMemento PerformUndo()
{
HistoryMemento redoMemento = new HistoryMementoModifyDrawing(metadata, managerId, drawingId, drawingName, filter);
DrawingSerializer.DeserializeModifyMemento(managerId, drawingId, data, metadata);
metadata.ModifiedDrawing(managerId, drawingId);
return(redoMemento);
}