diff --git a/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextBasedCache.java b/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextBasedCache.java
new file mode 100644
index 000000000000..b70655361b11
--- /dev/null
+++ b/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextBasedCache.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2000-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.jetbrains.python.psi.types;
+
+import com.intellij.psi.util.*;
+import com.intellij.util.Function;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Engine to cache something in map, where {@link TypeEvalContext} is used as key.
+ * This cache is weak-based (no memory leaks), thread safe and purges on any PSI change.
+ *
+ * @author Ilya.Kazakevich
+ */
+public final class TypeEvalContextBasedCache<T> {
+  /**
+   * Lock to sync
+   */
+  @NotNull
+  private final Object myLock = new Object();
+  @NotNull
+  private final CachedValue<Map<TypeEvalConstraints, T>> myCachedMapStorage;
+
+  @NotNull
+  private final Function<TypeEvalContext, T> myProvider;
+
+  /**
+   * @param manager       Cache manager to be used to store cache
+   * @param valueProvider engine to create value based on context.
+   */
+  public TypeEvalContextBasedCache(@NotNull final CachedValuesManager manager,
+                                   @NotNull final Function<TypeEvalContext, T> valueProvider) {
+    myCachedMapStorage = manager.createCachedValue(new MapCreator<T>(), false);
+    myProvider = valueProvider;
+  }
+
+  /**
+   * Returns value (executes provider to obtain new if no any and stores it in cache)
+   * @param context to be used as key
+   * @return value
+   */
+  @NotNull
+  public T getValue(@NotNull final TypeEvalContext context) {
+
+    // Map is not thread safe, and "getValue" is not atomic. I do not want several maps to be created.
+    synchronized (myLock) {
+      final Map<TypeEvalConstraints, T> map = myCachedMapStorage.getValue();
+      T value = map.get(context.getConstraints());
+      if (value != null) {
+        return value;
+      }
+      // This is the same value, semantically: value for context-key
+      //noinspection ReuseOfLocalVariable
+      value = myProvider.fun(context);
+      map.put(context.getConstraints(), value);
+      return value;
+    }
+  }
+
+  /**
+   * Provider that creates map to store cache. Map depends on PSI modification
+   */
+  private static final class MapCreator<T> implements CachedValueProvider<Map<TypeEvalConstraints, T>> {
+    @Nullable
+    @Override
+    public Result<Map<TypeEvalConstraints, T>> compute() {
+      // This method is called if cache is empty. Create new map for it.
+      final HashMap<TypeEvalConstraints, T> map = new HashMap<TypeEvalConstraints, T>();
+      return new Result<Map<TypeEvalConstraints, T>>(map, PsiModificationTracker.MODIFICATION_COUNT);
+    }
+  }
+}
diff --git a/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextCacheImpl.java b/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextCacheImpl.java
index ab40e47309e3..9d5f9f69fbf0 100644
--- a/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextCacheImpl.java
+++ b/python/psi-api/src/com/jetbrains/python/psi/types/TypeEvalContextCacheImpl.java
@@ -15,15 +15,9 @@
  */
 package com.jetbrains.python.psi.types;
 
-import com.intellij.psi.util.CachedValue;
-import com.intellij.psi.util.CachedValueProvider;
 import com.intellij.psi.util.CachedValuesManager;
-import com.intellij.psi.util.PsiModificationTracker;
+import com.intellij.util.Function;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-import java.util.HashMap;
-import java.util.Map;
 
 /**
  * Caches context by their constraints (to prevent context cache loss). Flushes cache every PSI change or low memory conditions.
@@ -34,53 +28,27 @@ import java.util.Map;
  */
 final class TypeEvalContextCacheImpl implements TypeEvalContextCache {
 
-  /**
-   * Producer to create map to store cache
-   */
   @NotNull
-  private static final MapCreator MAP_CREATOR = new MapCreator();
-
-  /**
-   * Lock to sync
-   */
+  private static final Function<TypeEvalContext, TypeEvalContext> VALUE_PROVIDER = new MyValueProvider();
   @NotNull
-  private final Object myLock = new Object();
-
-  @NotNull
-  private final CachedValue<Map<TypeEvalConstraints, TypeEvalContext>> myCachedMapStorage;
-
+  private final TypeEvalContextBasedCache<TypeEvalContext> myCache;
 
   TypeEvalContextCacheImpl(@NotNull final CachedValuesManager manager) {
-    myCachedMapStorage = manager.createCachedValue(MAP_CREATOR, false);
+    myCache = new TypeEvalContextBasedCache<TypeEvalContext>(manager, VALUE_PROVIDER);
   }
 
 
   @NotNull
   @Override
   public TypeEvalContext getContext(@NotNull final TypeEvalContext standard) {
-
-    // Map is not thread safe, and "getValue" is not atomic. I do not want several maps to be created.
-    synchronized (myLock) {
-      final Map<TypeEvalConstraints, TypeEvalContext> map = myCachedMapStorage.getValue();
-      final TypeEvalContext context = map.get(standard.getConstraints());
-      if (context != null) {
-        return context;
-      }
-      map.put(standard.getConstraints(), standard);
-      return standard;
-    }
+    return myCache.getValue(standard);
   }
 
-  /**
-   * Provider that creates map to store cache. Map depends on PSI modification
-   */
-  private static final class MapCreator implements CachedValueProvider<Map<TypeEvalConstraints, TypeEvalContext>> {
-    @Nullable
+  private static class MyValueProvider implements Function<TypeEvalContext, TypeEvalContext> {
     @Override
-    public Result<Map<TypeEvalConstraints, TypeEvalContext>> compute() {
-      // This method is called if cache is empty. Create new map for it.
-      final HashMap<TypeEvalConstraints, TypeEvalContext> map = new HashMap<TypeEvalConstraints, TypeEvalContext>();
-      return new Result<Map<TypeEvalConstraints, TypeEvalContext>>(map, PsiModificationTracker.MODIFICATION_COUNT);
+    public TypeEvalContext fun(final TypeEvalContext param) {
+      // key and value are both context here. If no context stored, then key is stored. Old one is returned otherwise to cache.
+      return param;
     }
   }
 }
diff --git a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
index 5c0414276a99..3ac39612cc39 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
@@ -72,14 +72,25 @@ public class PyClassImpl extends PyBaseElementImpl<PyClassStub> implements PyCla
 
   public static final PyClass[] EMPTY_ARRAY = new PyClassImpl[0];
 
-  private List<PyTargetExpression> myInstanceAttributes;
+  /**
+   * Ancestors cache is lazy because provider ({@link com.jetbrains.python.psi.impl.PyClassImpl.CachedAncestorsProvider}) needs
+   * {@link #getProject()} which is notavailable during consructor time.
+   */
+  private TypeEvalContextBasedCache<List<PyClassLikeType>> myAncestorsCache;
 
-  private volatile Map<String, Property> myPropertyCache;
+  /**
+   * Lock to create {@link #myAncestorsCache} in lazy way.
+   */
+  @NotNull
+  private final Object myAncestorsCacheLock = new Object();
 
-  private class CachedAncestorsProvider implements ParameterizedCachedValueProvider<List<PyClassLikeType>, TypeEvalContext> {
+  /**
+   * Engine to create list of ancestors based on context
+   */
+  private class CachedAncestorsProvider implements Function<TypeEvalContext, List<PyClassLikeType>> {
     @Nullable
     @Override
-    public CachedValueProvider.Result<List<PyClassLikeType>> compute(@NotNull TypeEvalContext context) {
+    public List<PyClassLikeType> fun(@NotNull TypeEvalContext context) {
       List<PyClassLikeType> ancestorTypes;
       if (isNewStyleClass(context)) {
         try {
@@ -102,10 +113,14 @@ public class PyClassImpl extends PyBaseElementImpl<PyClassStub> implements PyCla
       else {
         ancestorTypes = getOldStyleAncestorTypes(context);
       }
-      return CachedValueProvider.Result.create(ancestorTypes, PsiModificationTracker.MODIFICATION_COUNT);
+      return ancestorTypes;
     }
   }
 
+  private List<PyTargetExpression> myInstanceAttributes;
+
+  private volatile Map<String, Property> myPropertyCache;
+
   private final Key<ParameterizedCachedValue<List<PyClassLikeType>, TypeEvalContext>> myCachedValueKey = Key.create("cached ancestors");
   private final CachedAncestorsProvider myCachedAncestorsProvider = new CachedAncestorsProvider();
 
@@ -135,6 +150,25 @@ public class PyClassImpl extends PyBaseElementImpl<PyClassStub> implements PyCla
     super(stub, nodeType);
   }
 
+  /**
+   * @return ancestors cache. It is created lazyly if needed.
+   */
+  @NotNull
+  private TypeEvalContextBasedCache<List<PyClassLikeType>> getAncestorsCache() {
+    if (myAncestorsCache != null) {
+      return myAncestorsCache;
+    }
+    synchronized (myAncestorsCacheLock) {
+      if (myAncestorsCache == null) {
+        myAncestorsCache = new TypeEvalContextBasedCache<List<PyClassLikeType>>(
+          CachedValuesManager.getManager(getProject()),
+          new CachedAncestorsProvider()
+        );
+      }
+      return myAncestorsCache;
+    }
+  }
+
   public PsiElement setName(@NotNull String name) throws IncorrectOperationException {
     final ASTNode nameElement = PyUtil.createNewName(this, name);
     final ASTNode node = getNameNode();
@@ -1274,9 +1308,7 @@ public class PyClassImpl extends PyBaseElementImpl<PyClassStub> implements PyCla
   @NotNull
   @Override
   public List<PyClassLikeType> getAncestorTypes(@NotNull TypeEvalContext context) {
-    // TODO: Return different cached copies depending on the type eval context parameters
-    final CachedValuesManager manager = CachedValuesManager.getManager(getProject());
-    return manager.getParameterizedCachedValue(this, myCachedValueKey, myCachedAncestorsProvider, false, context);
+    return getAncestorsCache().getValue(context);
   }
 
   @Nullable