(.module:
  [lux #*
   [type
    abstract]]
  [//
   [signature (#+ Signature)]])

(abstract: #export (Key k)
  Signature

  (def: #export signature
    (-> (Key Any) Signature)
    (|>> :representation))

  (def: #export (key signature sample)
    (All [d] (-> Signature d (Key d)))
    (:abstraction signature))
  )