truncateHistory :: History -> Topped AccessNr -> Either String History
truncateHistory h@(HistoryRoot _) (Finite (AccessNr 0)) = Right h
truncateHistory :: History -> Topped AccessNr -> Either String History
truncateHistory h@(HistoryRoot _) (Finite (AccessNr 0)) = Right h
truncateHistory h@(HistoryRoot _) (Finite (AccessNr 0)) = Right h