val initial_status: status
-val process_item: (status -> Aut.item -> 'a) -> status -> Aut.item -> 'a
+val process_unit: (status -> Aut.unit -> 'a) -> status -> Aut.unit -> 'a
-val get_counters: (int -> int -> int -> 'a) -> status -> 'a
+val get_counters: (int -> int -> int -> int -> 'a) -> status -> 'a