Clojure multimethod giving unexpected null pointer -

i'm having hard time getting multimethods in clojure work expect. distillation of code follows.

(defn commandtype [_ command] (:command-type command))  (defmulti testmulti commandtype)  (defmethod testmulti :one [game command] (str "blah"))  (defmethod testmulti :default [& args] "cannot understand")  (testmulti "something" {:command-type :one})  (commandtype "something" {:command-type :one}) 

now expect here have method commandtype called on arguments of course return :one should send first defmethod instead null pointer exception. simplest invocation of multimethod come gives me null pointer:

(defmulti simplemulti :key)  (defmethod simplemulti "basic" [params] "basic value")  (simplemulti {:key "basic"}) 

and yet example in clojure docs located here works fine. there fundamental i'm doing wrong?

so far can see, works.

given

(defmulti testmulti (fn [_ command] (:command-type command)))  (defmethod testmulti :one [game command] (str "blah"))  (defmethod testmulti :default [& args] "cannot understand") 

then

(testmulti "something" {:command-type :one}) ; "blah"  (testmulti "something" {:command-type :two}) ; "cannot understand"  (testmulti "something" 5) ; "cannot understand" 

as expected.

i reset repl before running above afresh.

and simple example works too. given

(defmulti simplemulti :key)  (defmethod simplemulti "basic" [params] "basic value") 

then

(simplemulti {:key "basic"}) ; "basic value"