getDeltaScript :: History -> History -> Maybe [HistoryEntry]
getDeltaScript (HistoryRoot _) end = Just $ historyGetHeList end
getDeltaScript :: History -> History -> Maybe [HistoryEntry]
getDeltaScript (HistoryRoot _) end = Just $ historyGetHeList end
getDeltaScript (HistoryRoot _) end = Just $ historyGetHeList end