deal with some differences under Python 3

src/Missing/__init__.py

@@ -1,7 +1,13 @@
 import os
+import sys
 
 from ExtensionClass import Base
 
+if sys.version_info >= (3, ):
+    PY3 = True
+else:
+    PY3 = False
+
 
 class Missing(Base):
 
@@ -22,13 +28,19 @@ def __reduce__(self):
             return 'V'
         return (type(self), ())
 
-    def __nonzero__(self):
+    def __bool__(self):
         return False
 
-    def __cmp__(self, other):
-        if self is notMissing:
-            return -1
-        return other is notMissing
+    if not PY3:
+        __nonzero__ = __bool__
+
+        def __coerce__(self, other):
+            return (self, notMissing)
+
+        def __cmp__(self, other):
+            if self is notMissing:
+                return -1
+            return other is notMissing
 
     def __eq__(self, other):
         if self is notMissing:
@@ -72,9 +84,6 @@ def _change(self):
 
     __neg__ = __pos__ = __abs__ = __invert__ = _change
 
-    def __coerce__(self, other):
-        return (self, notMissing)
-
     def __setattr__(self, key, value):
         raise AttributeError(key)
 

src/Missing/tests.py

@@ -5,9 +5,11 @@
     def u(value):
         return str(value, 'utf-8')
     long = int
+    PY3 = True
 else:
     def u(value):
         return unicode(value, 'utf-8')
+    PY3 = False
 
 
 class ValueTests(object):
@@ -174,6 +176,8 @@ def test_xor(self):
         self.assertEqual(value, value ^ 2)
 
     def test_coerce(self):
+        if PY3:
+            return
         from Missing import notMissing
         value = self._make_one()
         self.assertEqual(coerce(value, 1), (value, notMissing))