val listUsers : int -> (bool * Init.user) list
(* List users and indicate whether they participated in a transaction *)
+ val lookupHostingUsage : int -> string option
+
type charge = {trn : int, usr : int, amount : real}
val addCharge : charge -> unit
val addHostingCharges : hosting -> unit
val equalizeBalances : unit -> unit
-end
\ No newline at end of file
+
+ val costBase : real -> real
+end