use assert[Not]In where appropriate
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 57b69e6..797b887 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -1654,7 +1654,7 @@
         self.assertNotIn(-1, c1)
         for i in range(10):
             self.assertIn(i, c1)
-        self.assertFalse(10 in c1)
+        self.assertNotIn(10, c1)
         # Test the default behavior for dynamic classes
         class D(object):
             def __getitem__(self, i):
@@ -1677,7 +1677,7 @@
         self.assertNotIn(-1, d1)
         for i in range(10):
             self.assertIn(i, d1)
-        self.assertFalse(10 in d1)
+        self.assertNotIn(10, d1)
         # Test overridden behavior
         class Proxy(object):
             def __init__(self, x):
@@ -1721,10 +1721,10 @@
         self.assertEqual(str(p0), "Proxy:0")
         self.assertEqual(repr(p0), "Proxy(0)")
         p10 = Proxy(range(10))
-        self.assertFalse(-1 in p10)
+        self.assertNotIn(-1, p10)
         for i in range(10):
             self.assertIn(i, p10)
-        self.assertFalse(10 in p10)
+        self.assertNotIn(10, p10)
 
     def test_weakrefs(self):
         # Testing weak references...