MakeSeeded.1-Hval hash : int -> t -> intsame as Hashtbl.SeededHashedType
equality predicate used to compare a key with the one in a container. Can return EDead if the keys in the container are dead
create key data creates a container from some initials keys and one data
val get_data : 'a container -> 'a optionget_data cont returns the data if it is alive
val check_key : 'a container -> boolcheck_key cont checks if all the keys contained in the data are alive