let rec play (card_list : list<card>, held_list : list<card>, move_list : list<move>, goal : int, sum : int, thres : int) : list<move> =
        match goal - sum with
        | 0 -> move_list
        | var1 with var1 > 10 -> match card_list with
                           | head :: tail -> play(tail, held_list @ [head], move_list @ [Draw], goal, sum + card_value(head))
                           | [] -> move_list @ [Draw]
        | var1 with var1 <= 10 -> match card_list with
                                  | head :: tail -> match hint(head, held_list) with
                                                    | None -> move_list
                                                    | Some x -> move_list @ [Discard(x)] @ [Draw]