fact: Definition returnEnum {A : Type} (x : A) : E A := MkEnum (fun _ => retLazyList x).
imports: ZArith List mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool ssrnat) Numbers.BinNums Classes.RelationClasses ExtLib.Structures(Functor Applicative) QuickChick(Sets Tactics Producer LazyList RandomQC)