Hi, I'm getting a strange error when running the http://malli.io example of "Pet" in Clojure (not Clojurescript). Code here:

(def PetMalli
    [:schema {:registry {"Pet" [:map
                                [:type keyword?]
                                [:name string?]]
                         "Cat" [:merge
                                "Pet"
                                [:map
                                 [:type [:= "Cat"]]
                                 [:huntingSkill [:enum {:description "The measured skill for hunting"}
                                                 :clueless, :lazy, :adventurous, :aggressive]]]]
                         "Dog" [:merge
                                "Pet"
                                [:map
                                 [:type [:= "Dog"]]
                                 [:packSize [:int {:min 0,
                                                   :default 0
                                                   :description "the size of the pack the dog is from"}]]]]}}
     [:multi {:dispatch :type} "Cat" "Dog"]])

(m/validate PetMalli {:type "Cat", :name "Viivi", :huntingSkill :adventurous})

Message: Execution error (ExceptionInfo) at malli.core/-fail! (core.cljc:136). :malli.core/invalid-schema {:schema :merge}

Could anyone give me some pointers? We want to use :merge for some inheritance-like constraints in our schema, which is very similar to the "Pet" example.