Definition normalize {X} `{Finite X} (d : dist X) : dist X.
refine {|
dist_pmf := map (fun x => (x, eval_dist d (Classes.eqb x))) enum;
dist_law := _;
|}.

Lemma sumFQ_2D {X Y} `{Finite X, Finite Y} (f : X * Y -> Q) :
sumFQ f == sumFQ (fun x => sumFQ (fun y => f (x,y))).