diff --git a/python/psi-api/src/com/jetbrains/python/psi/LanguageLevel.java b/python/psi-api/src/com/jetbrains/python/psi/LanguageLevel.java
index 8229dfdd43df..1c56c2b60f3d 100644
--- a/python/psi-api/src/com/jetbrains/python/psi/LanguageLevel.java
+++ b/python/psi-api/src/com/jetbrains/python/psi/LanguageLevel.java
@@ -15,11 +15,14 @@
  */
 package com.jetbrains.python.psi;
 
+import com.google.common.collect.ImmutableList;
 import com.intellij.openapi.util.Key;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.List;
+
 /**
  * @author yole
  */
@@ -35,6 +38,19 @@ public enum LanguageLevel {
   PYTHON34(34, true, false, true, true),
   PYTHON35(35, true, false, true, true);
 
+  public static List<LanguageLevel> ALL_LEVELS = ImmutableList.<LanguageLevel>builder()
+    .add(PYTHON24)
+    .add(PYTHON25)
+    .add(PYTHON26)
+    .add(PYTHON27)
+    .add(PYTHON30)
+    .add(PYTHON31)
+    .add(PYTHON32)
+    .add(PYTHON33)
+    .add(PYTHON34)
+    .add(PYTHON35)
+    .build();
+
   private static LanguageLevel DEFAULT2 = PYTHON27;
   private static LanguageLevel DEFAULT3 = PYTHON34;
 
diff --git a/python/src/com/jetbrains/python/validation/UnsupportedFeaturesUtil.java b/python/src/com/jetbrains/python/validation/UnsupportedFeaturesUtil.java
index 4018b339fc5d..a84651c009ab 100644
--- a/python/src/com/jetbrains/python/validation/UnsupportedFeaturesUtil.java
+++ b/python/src/com/jetbrains/python/validation/UnsupportedFeaturesUtil.java
@@ -41,8 +41,8 @@ public class UnsupportedFeaturesUtil {
   public static Map<LanguageLevel, Set<String>> BUILTINS = new HashMap<LanguageLevel, Set<String>>();
   public static Map<LanguageLevel, Set<String>> MODULES = new HashMap<LanguageLevel, Set<String>>();
   public static Map<String, Map<LanguageLevel, Set<String>>> CLASS_METHODS = new HashMap<String, Map<LanguageLevel, Set<String>>>();
+  public static final List<String> ALL_LANGUAGE_LEVELS = new ArrayList<String>();
 
-  public static Vector<String> ALL_LANGUAGE_LEVELS;
   static {
     try {
       fillMaps();
@@ -52,7 +52,9 @@ public class UnsupportedFeaturesUtil {
       Logger log = Logger.getInstance(UnsupportedFeaturesUtil.class.getName());
       log.error("Cannot find \"versions.xml\". " + e.getMessage());
     }
-    fillAllLanguageLeves();
+    for (LanguageLevel level : LanguageLevel.ALL_LEVELS) {
+      ALL_LANGUAGE_LEVELS.add(level.toString());
+    }
   }
 
   private static void fillTestCaseMethods() throws IOException {
@@ -72,19 +74,6 @@ public class UnsupportedFeaturesUtil {
     }
   }
 
-  private static void fillAllLanguageLeves() {
-    ALL_LANGUAGE_LEVELS = new Vector<String>();
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON24.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON25.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON26.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON27.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON30.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON31.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON32.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON33.toString());
-    ALL_LANGUAGE_LEVELS.add(LanguageLevel.PYTHON34.toString());
-  }
-
   private static void fillMaps() throws IOException {
     Logger log = Logger.getInstance(UnsupportedFeaturesUtil.class.getName());
     FileReader reader = new FileReader(PythonHelpersLocator.getHelperPath("/tools/versions.xml"));