Don't call identity on error function

src/propeller/core.cljc

@@ -23,7 +23,6 @@
   ;; Creates problems
   (require (symbol (str "propeller.problems." (first args))))
   (gp/gp
-    (update-in
     (merge
       {:instructions            (eval-problem-var (first args) "instructions")
        :error-function          (eval-problem-var (first args) "error-function")
@@ -40,6 +39,4 @@
        :PSB2-problem            (clojure.string/replace (first args) #"PSB2." "")}
       (apply hash-map
              (map #(if (and (string? %) (not (.contains % "/"))) (read-string %) %)
-                    (rest args))))
-      [:error-function]
-      identity)))
+                  (rest args))))))