diff -r bb6cababa5bd -r 63cf8ba004b8 Lib/test/test_dict_jy.py
--- a/Lib/test/test_dict_jy.py	Sun May 17 09:10:22 2015 +0100
+++ b/Lib/test/test_dict_jy.py	Fri Jun 19 11:57:29 2015 -0700
@@ -257,6 +257,128 @@
         return newdict
 
 
+class Issue2367DictTest(unittest.TestCase):
+
+    class HashDict(dict):
+        """Dict with __hash__ and __eq__ that checks both type and dict values."""
+        def __hash__(self):
+            return hash(frozenset(self.items()))
+
+        def __eq__(self, other):
+            if type(self) is type(other):
+                return dict.__eq__(self, other)
+            return False
+
+        def __ne__(self, other):
+            return not(self == other)
+
+    class Dict1(HashDict):
+        pass
+
+    class Dict2(HashDict):
+        pass
+
+    a = Dict1()
+    b = Dict2()
+
+    def test_equal_hashes(self):
+        """Ensure that we are in fact dealing with a hash collision.
+
+        """
+        self.assertEqual(hash(self.a), hash(self.b))
+
+    def test_unequal_objects(self):
+        """Test that the objects do in fact compare unequal, and should be
+        simultaneously usable as keys.
+
+        """
+        # Ensures no funny business is going on with __ne__ and __eq__
+        self.assertTrue(self.a != self.b)
+        self.assertTrue(self.b != self.a)
+        self.assertFalse(self.a == self.b)
+        self.assertFalse(self.b == self.a)
+        self.assertFalse(self.a.__eq__(self.b))
+        self.assertFalse(self.b.__eq__(self.a))
+
+    def test_distinct_as_keys(self):
+        """Test that both elements may be used as different keys in a dict.
+
+        """
+        # Python should first compare by hash. As the hashes are the same, it
+        # should proceed to compare for equality. As Dict1 and Dict2 have
+        # different types, their __eq__ methods will return false, thus we
+        # should have a hash collision, and both elements should be in the
+        # dict.
+        #
+        # In CPython and PyPy, this is what happens. Jython seems to ignore
+        # the custom __eq__.
+        d = {}
+        d[self.a] = 1
+        d[self.b] = 2
+        self.assertEqual(len(d), 2)
+
+    def test_both_in_set(self):
+        """That both objects may be placed in a set.
+
+        """
+        s = {self.a, self.b}
+        self.assertIn(self.a, s)
+        self.assertIn(self.b, s)
+
+    def test_distinct_in_set(self):
+        """Test that both elements are viewd as distinct in a set.
+
+        """
+        s = {self.a, self.b}
+        self.assertEqual(len(s), 2)
+
+    def test_hash_collisions_on_same_type(self):
+        """Test that hash collisions on same type are resolved normally.
+
+        """
+        d1 = self.Dict1({2**128: 1})
+        d2 = self.Dict1({hash(2**128): 1})
+        self.assertEqual(hash(d1), hash(d2))
+        d = {}
+        d[d1] = 1
+        d[d2] = 2
+        self.assertEqual(2, len(d))
+
+class DictDerivedTest(unittest.TestCase):
+
+    class HashDict(dict):
+        def __hash__(self):
+            return hash(frozenset(self.items()))
+        # no __eq__ defined
+
+    class Dict1(HashDict):
+        pass
+
+    class Dict2(HashDict):
+        pass
+
+    a = Dict1()
+    b = Dict2()
+
+    def test_noeq_equal_hashes(self):
+        self.assertTrue(self.a == self.b)
+        self.assertTrue(self.b == self.a)
+        self.assertFalse(self.a != self.b)
+        self.assertFalse(self.b != self.a)
+
+    def test_noeq_collides_in_set(self):
+        s = {self.a, self.b}
+        self.assertEqual(1, len(s))
+
+    def test_unhashable_dict(self):
+        class UnhashableDict(dict):
+            pass
+
+        x = UnhashableDict()
+        with self.assertRaises(TypeError):
+            s = {x,}
+
+
 def test_main():
     test_support.run_unittest(
         DictInitTest,
@@ -265,7 +387,9 @@
         DerivedDictTest,
         JavaIntegrationTest,
         JavaDictTest,
-        PyStringMapTest)
+        PyStringMapTest,
+        Issue2367DictTest,
+        DictDerivedTest)
 
 if __name__ == '__main__':
     test_main()
diff -r bb6cababa5bd -r 63cf8ba004b8 src/org/python/core/PyDictionary.java
--- a/src/org/python/core/PyDictionary.java	Sun May 17 09:10:22 2015 +0100
+++ b/src/org/python/core/PyDictionary.java	Fri Jun 19 11:57:29 2015 -0700
@@ -257,7 +257,8 @@
         PyType thisType = getType();
         PyType otherType = otherObj.getType();
         if (otherType != thisType && !thisType.isSubType(otherType)
-                && !otherType.isSubType(thisType) || otherType == PyObject.TYPE) {
+                && !otherType.isSubType(thisType) && !otherType.isSubType(PyDictionary.TYPE)
+                || otherType == PyObject.TYPE) {
             return null;
         }
         PyDictionary other = (PyDictionary)otherObj;
diff -r bb6cababa5bd -r 63cf8ba004b8 src/org/python/core/PyDictionaryDerived.java
--- a/src/org/python/core/PyDictionaryDerived.java	Sun May 17 09:10:22 2015 +0100
+++ b/src/org/python/core/PyDictionaryDerived.java	Fri Jun 19 11:57:29 2015 -0700
@@ -21,7 +21,7 @@
     public void __del_derived__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__del__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__();
         }
     }
@@ -98,7 +98,7 @@
     public PyString __str__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__str__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyString)
                 return(PyString)res;
@@ -110,7 +110,7 @@
     public PyString __repr__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__repr__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyString)
                 return(PyString)res;
@@ -122,7 +122,7 @@
     public PyString __hex__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__hex__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyString)
                 return(PyString)res;
@@ -134,7 +134,7 @@
     public PyString __oct__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__oct__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyString)
                 return(PyString)res;
@@ -146,7 +146,7 @@
     public PyFloat __float__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__float__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyFloat)
                 return(PyFloat)res;
@@ -158,7 +158,7 @@
     public PyComplex __complex__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__complex__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyComplex)
                 return(PyComplex)res;
@@ -170,7 +170,7 @@
     public PyObject __pos__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__pos__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__pos__();
     }
@@ -178,7 +178,7 @@
     public PyObject __neg__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__neg__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__neg__();
     }
@@ -186,7 +186,7 @@
     public PyObject __abs__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__abs__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__abs__();
     }
@@ -194,7 +194,7 @@
     public PyObject __invert__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__invert__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__invert__();
     }
@@ -202,7 +202,7 @@
     public PyObject __reduce__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__reduce__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__reduce__();
     }
@@ -210,7 +210,7 @@
     public PyObject __dir__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__dir__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         return super.__dir__();
     }
@@ -218,7 +218,7 @@
     public PyObject __add__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__add__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -230,7 +230,7 @@
     public PyObject __radd__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__radd__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -242,7 +242,7 @@
     public PyObject __sub__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__sub__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -254,7 +254,7 @@
     public PyObject __rsub__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rsub__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -266,7 +266,7 @@
     public PyObject __mul__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__mul__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -278,7 +278,7 @@
     public PyObject __rmul__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rmul__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -290,7 +290,7 @@
     public PyObject __div__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__div__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -302,7 +302,7 @@
     public PyObject __rdiv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rdiv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -314,7 +314,7 @@
     public PyObject __floordiv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__floordiv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -326,7 +326,7 @@
     public PyObject __rfloordiv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rfloordiv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -338,7 +338,7 @@
     public PyObject __truediv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__truediv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -350,7 +350,7 @@
     public PyObject __rtruediv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rtruediv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -362,7 +362,7 @@
     public PyObject __mod__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__mod__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -374,7 +374,7 @@
     public PyObject __rmod__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rmod__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -386,7 +386,7 @@
     public PyObject __divmod__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__divmod__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -398,7 +398,7 @@
     public PyObject __rdivmod__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rdivmod__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -410,7 +410,7 @@
     public PyObject __rpow__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rpow__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -422,7 +422,7 @@
     public PyObject __lshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__lshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -434,7 +434,7 @@
     public PyObject __rlshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rlshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -446,7 +446,7 @@
     public PyObject __rshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -458,7 +458,7 @@
     public PyObject __rrshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rrshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -470,7 +470,7 @@
     public PyObject __and__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__and__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -482,7 +482,7 @@
     public PyObject __rand__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rand__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -494,7 +494,7 @@
     public PyObject __or__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__or__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -506,7 +506,7 @@
     public PyObject __ror__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ror__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -518,7 +518,7 @@
     public PyObject __xor__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__xor__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -530,7 +530,7 @@
     public PyObject __rxor__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__rxor__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -542,7 +542,7 @@
     public PyObject __lt__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__lt__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -554,7 +554,7 @@
     public PyObject __le__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__le__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -566,7 +566,7 @@
     public PyObject __gt__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__gt__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -578,7 +578,7 @@
     public PyObject __ge__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ge__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -590,7 +590,7 @@
     public PyObject __eq__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__eq__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -602,7 +602,7 @@
     public PyObject __ne__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ne__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -614,7 +614,7 @@
     public PyObject __format__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__format__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -626,7 +626,7 @@
     public PyObject __iadd__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__iadd__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -638,7 +638,7 @@
     public PyObject __isub__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__isub__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -650,7 +650,7 @@
     public PyObject __imul__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__imul__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -662,7 +662,7 @@
     public PyObject __idiv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__idiv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -674,7 +674,7 @@
     public PyObject __ifloordiv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ifloordiv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -686,7 +686,7 @@
     public PyObject __itruediv__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__itruediv__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -698,7 +698,7 @@
     public PyObject __imod__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__imod__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -710,7 +710,7 @@
     public PyObject __ipow__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ipow__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -722,7 +722,7 @@
     public PyObject __ilshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ilshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -734,7 +734,7 @@
     public PyObject __irshift__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__irshift__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -746,7 +746,7 @@
     public PyObject __iand__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__iand__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -758,7 +758,7 @@
     public PyObject __ior__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ior__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -770,7 +770,7 @@
     public PyObject __ixor__(PyObject other) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__ixor__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(other);
             if (res==Py.NotImplemented)
                 return null;
@@ -782,7 +782,7 @@
     public PyObject __int__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__int__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyInteger||res instanceof PyLong)
                 return res;
@@ -794,7 +794,7 @@
     public PyObject __long__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__long__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyLong||res instanceof PyInteger)
                 return res;
@@ -803,10 +803,11 @@
         return super.__long__();
     }
 
+    @Override
     public int hashCode() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__hash__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyInteger) {
                 return((PyInteger)res).getValue();
@@ -822,10 +823,26 @@
         return super.hashCode();
     }
 
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof PyObject) {
+            PyObject res = __eq__((PyObject) obj);
+            if (res == null) {
+                // not sure what an appropriate message should be
+                throw Py.TypeError(String.format("unhashable type: '%.200s'",getType().fastGetName()));
+            }
+            return res.__nonzero__();
+        }
+        return super.equals(obj);
+    }
+
     public PyUnicode __unicode__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__unicode__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyUnicode)
                 return(PyUnicode)res;
@@ -883,7 +900,7 @@
     public int __len__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__len__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             return res.asInt();
         }
@@ -893,7 +910,7 @@
     public PyObject __iter__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__iter__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__();
         impl=self_type.lookup("__getitem__");
         if (impl==null)
@@ -904,7 +921,7 @@
     public PyObject __iternext__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("next");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             try {
                 return impl.__get__(this,self_type).__call__();
             } catch (PyException exc) {
@@ -919,7 +936,7 @@
     public PyObject __finditem__(PyObject key) { // ???
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__getitem__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             try {
                 return impl.__get__(this,self_type).__call__(key);
             } catch (PyException exc) {
@@ -933,7 +950,7 @@
     public PyObject __finditem__(int key) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__getitem__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             try {
                 return impl.__get__(this,self_type).__call__(new PyInteger(key));
             } catch (PyException exc) {
@@ -965,7 +982,7 @@
 
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__getitem__");
-        if (impl!=null)
+        if (impl != null && impl != Py.None)
             return impl.__get__(this,self_type).__call__(key);
         return super.__getitem__(key);
     }
@@ -973,7 +990,7 @@
     public void __setitem__(PyObject key,PyObject value) { // ???
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__setitem__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(key,value);
             return;
         }
@@ -986,7 +1003,7 @@
         }
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__getslice__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject[]indices=PySlice.indices2(this,start,stop);
             return impl.__get__(this,self_type).__call__(indices[0],indices[1]);
         }
@@ -1000,7 +1017,7 @@
         }
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__setslice__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject[]indices=PySlice.indices2(this,start,stop);
             impl.__get__(this,self_type).__call__(indices[0],indices[1],value);
             return;
@@ -1015,7 +1032,7 @@
         }
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__delslice__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject[]indices=PySlice.indices2(this,start,stop);
             impl.__get__(this,self_type).__call__(indices[0],indices[1]);
             return;
@@ -1026,7 +1043,7 @@
     public void __delitem__(PyObject key) { // ???
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__delitem__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(key);
             return;
         }
@@ -1036,7 +1053,7 @@
     public PyObject __call__(PyObject args[],String keywords[]) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__call__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             return impl.__get__(this,self_type).__call__(args,keywords);
         }
         return super.__call__(args,keywords);
@@ -1049,7 +1066,7 @@
     public void __setattr__(String name,PyObject value) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__setattr__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(PyString.fromInterned(name),value);
             //CPython does not support instance-acquired finalizers.
             //So we don't check for __del__ here.
@@ -1061,7 +1078,7 @@
     public void __delattr__(String name) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__delattr__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(PyString.fromInterned(name));
             return;
         }
@@ -1071,7 +1088,7 @@
     public PyObject __get__(PyObject obj,PyObject type) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__get__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             if (obj==null)
                 obj=Py.None;
             if (type==null)
@@ -1084,7 +1101,7 @@
     public void __set__(PyObject obj,PyObject value) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__set__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(obj,value);
             return;
         }
@@ -1094,7 +1111,7 @@
     public void __delete__(PyObject obj) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__delete__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             impl.__get__(this,self_type).__call__(obj);
             return;
         }
@@ -1104,7 +1121,7 @@
     public PyObject __pow__(PyObject other,PyObject modulo) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__pow__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res;
             if (modulo==null) {
                 res=impl.__get__(this,self_type).__call__(other);
@@ -1125,7 +1142,7 @@
     public PyObject __index__() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__index__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (res instanceof PyInteger||res instanceof PyLong) {
                 return res;
@@ -1147,7 +1164,7 @@
         // Otherwise, we call the derived __tojava__, if it exists:
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__tojava__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject delegate=impl.__get__(this,self_type).__call__(Py.java2py(c));
             if (delegate!=this)
                 return delegate.__tojava__(Object.class);
@@ -1158,7 +1175,7 @@
     public Object __coerce_ex__(PyObject o) {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__coerce__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__(o);
             if (res==Py.NotImplemented)
                 return Py.None;
@@ -1172,7 +1189,7 @@
     public String toString() {
         PyType self_type=getType();
         PyObject impl=self_type.lookup("__repr__");
-        if (impl!=null) {
+        if (impl != null && impl != Py.None) {
             PyObject res=impl.__get__(this,self_type).__call__();
             if (!(res instanceof PyString))
                 throw Py.TypeError("__repr__ returned non-string (type "+res.getType().fastGetName()+")");