create helper fn ugen-sequence-mode?

src/overtone/sc/machinery/ugen/specs.clj

@@ -224,16 +224,20 @@
         arg-list    (vec (map arg-map arg-names))]
     (assoc ugen :args arg-list :arg-map arg-map :orig-args args)))
 
+(defn ugen-sequence-mode?
+  [mode]
+  (or (= :append-sequence mode)
+      (= :append-sequence-set-num-outs mode)
+      (= :append-string mode)))
+
 (defn- append-seq-args
   "Handles argument modes :append-sequence and :append-sequence-set-num-outs,
   and :append-string  where some ugens take a seq or string for one argument
   which needs to be appended to the end of the argument list when sent to SC.
   (and in the case of strings need to be converted to a list of char ints)"
   [spec ugen]
   (let [args-specs     (args-with-specs (:args ugen) spec :mode)
-        pred           #(or (= :append-sequence (second %))
-                            (= :append-sequence-set-num-outs (second %))
-                            (= :append-string (second %)))
+        pred           #(ugen-sequence-mode? (second %))
         normal-args    (map first (remove pred args-specs))
         to-append      (filter pred args-specs)
         intify-strings (map (fn [[arg spec]]