From Undecidability.Shared.Libs.PSL Require Import FinTypes.
(* * Definition of prod as finType *)
Instance finTypeC_Prod (F1 F2: finType) : finTypeC (EqType (F1 * F2)).

(* A list produced by toOptionList contains None exactly once *)
Lemma NoneElement (X: eqType) (A: list X) :
count (toOptionList A) None = 1.