Hello! Finite maps from `"containers" Data.Map` look like they may form a Cartesian closed category. So it makes sense to ask if the rule _α ⇸ (β ⇸ γ) ≡ ⟨α; β⟩ ⇸ γ ≡ ⟨β; α⟩ ⇸ γ ≡ β ⇸ (α ⇸ γ)_ that holds in such categories does hold for finite maps. Note that, a map being a functor, this also may be seen as _f (g α) ≡ g (f α)_, which would work if maps were `Distributive` [1]. It looks to me as though the following definition might work: distribute = unionsWith union . mapWithKey (fmap . singleton) — And it works on simple examples. _(I checked the law `distribute ∘ distribute ≡ id` — it appears to be the only law required.)_ Is this definition correct? Is it already known and defined elsewhere? [1]: https://hackage.haskell.org/package/distributive-0.6.2.1/docs/Data-Distribut...