intuition.
eapply leRat_trans.
eapply RndInList_prob_h.
eapply leRat_terms; intuition.
Qed.
End RndInList.
Local Open Scope rat_scope.

Theorem RndNat_eq_any :
forall (eta : nat)(x : Bvector eta),
Pr  [a0 <-$ { 0 , 1 }^eta; ret (eqb x a0) ] == 1 / 2^eta.