Clojure hierarchy with multimethods

defmulti.clj

(defn dispatch-fn [o]
  (println (vals (select-keys o [:type :entity])))
  [(or (get o :type) ::any)
   (or (get o :entity) ::any)])

(def hiera (atom (-> (make-hierarchy)
                     (derive :string ::any)
                     (derive :object ::any))))

(ns-unmap *ns* 'mm)
(defmulti mm dispatch-fn :hierarchy hiera)

(defmethod mm [:object :number] [o] "OBJ number")
(defmethod mm [:object :string] [o] "OBJ STR")
(defmethod mm [:object ::any] [o] "OBJ ANY")
(defmethod mm :default [o] "DEFAULT")

(mm {:type :object :entity nil}) ;; OBJ ANY


(comment
 (isa? @hiera :object ::any))