val hash_fold_t : (Hash.state -> 'a -> Hash.state) -> (Hash.state -> 'b -> Hash.state) -> Hash.state -> ('a, 'b) t -> Hash.stateSequence.Merge_with_duplicates_elementval hash_fold_t : (Hash.state -> 'a -> Hash.state) -> (Hash.state -> 'b -> Hash.state) -> Hash.state -> ('a, 'b) t -> Hash.state