type session_id = Uuidm.t
exception UsernameCollision of string
+exception InvalidPassword
-val lookup_user : string -> (string * session_id option)
+val lookup_user : string -> (string * string * session_id option)
val user_of_session : session_id -> string
val add_user : string -> string -> unit
+val add_user_no_checkout : string -> string -> unit
+
+val check_pw : string -> string -> unit
+
val reset : unit -> unit