diff --git a/src/propeller/problems/string_classification.cljc b/src/propeller/problems/string_classification.cljc
index 42677c0..d6d0c0a 100755
--- a/src/propeller/problems/string_classification.cljc
+++ b/src/propeller/problems/string_classification.cljc
@@ -27,7 +27,7 @@
         :string_reverse
         :string_concat
         :string_length
-        :string_includes?
+        :string_contains
         'close
         0
         1
@@ -40,33 +40,45 @@
         "G"
         "T"))
 
+(defn train-and-test-data
+  []
+  (let [train-inputs ["GCG" "GACAG" "AGAAG" "CCCA" "GATTACA" "TAGG" "GACT"]
+        test-inputs ["GCGT" "GACTTAG" "AGTAAG" "TCCTCA" "GAACA" "AGG" "GAC"]]
+    {:train {:inputs  train-inputs
+             :outputs [false false false false true true true]}
+     :test  {:inputs  test-inputs
+             :outputs [true true true true false false false]}}))
+
 (defn error-function
   "Finds the behaviors and errors of an individual: Error is 0 if the value and
   the program's selected behavior match, or 1 if they differ, or 1000000 if no
   behavior is produced. The behavior is here defined as the final top item on
   the BOOLEAN stack."
-  [argmap individual]
-  (let [program (genome/plushy->push (:plushy individual) argmap)
-        inputs ["GCG" "GACAG" "AGAAG" "CCCA" "GATTACA" "TAGG" "GACT"]
-        correct-outputs [false false false false true true true]
-        outputs (map (fn [input]
-                       (state/peek-stack
-                         (interpreter/interpret-program
-                           program
-                           (assoc state/empty-state :input {:in1 input})
-                           (:step-limit argmap))
-                         :boolean))
-                     inputs)
-        errors (map (fn [correct-output output]
-                      (if (= output :no-stack-item)
-                        1000000
-                        (if (= correct-output output)
-                          0
-                          1)))
-                    correct-outputs
-                    outputs)]
-    (assoc individual
-      :behaviors outputs
-      :errors errors
-      :total-error #?(:clj (apply +' errors)
-                      :cljs (apply + errors)))))
\ No newline at end of file
+  ([argmap individual]
+   (error-function argmap individual :train))
+  ([argmap individual subset]
+   (let [program (genome/plushy->push (:plushy individual) argmap)
+         data (get (train-and-test-data) subset)
+         inputs (:inputs data)
+         correct-outputs (:outputs data)
+         outputs (map (fn [input]
+                        (state/peek-stack
+                          (interpreter/interpret-program
+                            program
+                            (assoc state/empty-state :input {:in1 input})
+                            (:step-limit argmap))
+                          :boolean))
+                      inputs)
+         errors (map (fn [correct-output output]
+                       (if (= output :no-stack-item)
+                         1000000
+                         (if (= correct-output output)
+                           0
+                           1)))
+                     correct-outputs
+                     outputs)]
+     (assoc individual
+       :behaviors outputs
+       :errors errors
+       :total-error #?(:clj  (apply +' errors)
+                       :cljs (apply + errors))))))
diff --git a/src/propeller/session.cljc b/src/propeller/session.cljc
index 9c54e98..20d62a6 100755
--- a/src/propeller/session.cljc
+++ b/src/propeller/session.cljc
@@ -135,4 +135,20 @@
                                   ;:umad 1
                                   }
         :elitism                 false
-        :diploid                 true})
\ No newline at end of file
+        :diploid                 true})
+
+#_(gp/gp {:instructions            propeller.problems.string-classification/instructions
+          :error-function          propeller.problems.string-classification/error-function
+          :max-generations         500
+          :population-size         500
+          :max-initial-plushy-size 100
+          :step-limit              200
+          :parent-selection        :lexicase
+          :tournament-size         5
+          :umad-rate               0.1
+          :diploid-flip-rate       0.1
+          :variation               {:umad 0.8
+                                    :diploid-flip 0.2
+                                    }
+          :elitism                 false
+          :diploid                 true})