intuition.
eapply (@ratAdd_add_same_l _ (Pr[c])).
rewrite ratSubtract_ratAdd_inverse_2.
rewrite <- sumList_support_bool.
eapply evalDist_lossless.
trivial.
eapply evalDist_le_1.
Qed.

Theorem evalDist_le_1_gen :
forall (A : Set)(eqd : EqDec A)(c : Comp A)(ls : list A),
NoDup ls ->
sumList ls (evalDist c) <= 1.