proposition: Lemma count_cons : forall P l x, count P (x::l) = count P l + If P x then 1 else 0.
proof: Proof. Proof using. gowith LibList.count_cons. Qed.
imports: TLC(LibTactics LibLogic LibOperation LibReflect LibProd LibNat LibInt LibOption LibWf) TLC(LibInt)