fact: Definition suchThatMaybe {A : Type} (g : G A) (p : A -> bool) : G (option A) := sized (fun n => retry n (suchThatMaybe1 g p)).
imports: Coq(String List ZArith Lia) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool ssrnat eqtype seq) QuickChick(RandomQC RoseTrees Sets Tactics Producer)