use assert[Not]In where appropriate
diff --git a/Lib/test/test_contains.py b/Lib/test/test_contains.py
index 73e0685..7138081 100644
--- a/Lib/test/test_contains.py
+++ b/Lib/test/test_contains.py
@@ -20,57 +20,57 @@
         a = base_set(1)
         b = set(1)
         c = seq(1)
-        self.assertTrue(1 in b)
-        self.assertTrue(0 not in b)
-        self.assertTrue(1 in c)
-        self.assertTrue(0 not in c)
+        self.assertIn(1, b)
+        self.assertNotIn(0, b)
+        self.assertIn(1, c)
+        self.assertNotIn(0, c)
         self.assertRaises(TypeError, lambda: 1 in a)
         self.assertRaises(TypeError, lambda: 1 not in a)
 
         # test char in string
-        self.assertTrue('c' in 'abc')
-        self.assertTrue('d' not in 'abc')
+        self.assertIn('c', 'abc')
+        self.assertNotIn('d', 'abc')
 
-        self.assertTrue('' in '')
-        self.assertTrue('' in 'abc')
+        self.assertIn('', '')
+        self.assertIn('', 'abc')
 
         self.assertRaises(TypeError, lambda: None in 'abc')
 
     if have_unicode:
         def test_char_in_unicode(self):
-            self.assertTrue('c' in unicode('abc'))
-            self.assertTrue('d' not in unicode('abc'))
+            self.assertIn('c', unicode('abc'))
+            self.assertNotIn('d', unicode('abc'))
 
-            self.assertTrue('' in unicode(''))
-            self.assertTrue(unicode('') in '')
-            self.assertTrue(unicode('') in unicode(''))
-            self.assertTrue('' in unicode('abc'))
-            self.assertTrue(unicode('') in 'abc')
-            self.assertTrue(unicode('') in unicode('abc'))
+            self.assertIn('', unicode(''))
+            self.assertIn(unicode(''), '')
+            self.assertIn(unicode(''), unicode(''))
+            self.assertIn('', unicode('abc'))
+            self.assertIn(unicode(''), 'abc')
+            self.assertIn(unicode(''), unicode('abc'))
 
             self.assertRaises(TypeError, lambda: None in unicode('abc'))
 
             # test Unicode char in Unicode
-            self.assertTrue(unicode('c') in unicode('abc'))
-            self.assertTrue(unicode('d') not in unicode('abc'))
+            self.assertIn(unicode('c'), unicode('abc'))
+            self.assertNotIn(unicode('d'), unicode('abc'))
 
             # test Unicode char in string
-            self.assertTrue(unicode('c') in 'abc')
-            self.assertTrue(unicode('d') not in 'abc')
+            self.assertIn(unicode('c'), 'abc')
+            self.assertNotIn(unicode('d'), 'abc')
 
     def test_builtin_sequence_types(self):
         # a collection of tests on builtin sequence types
         a = range(10)
         for i in a:
-            self.assertTrue(i in a)
-        self.assertTrue(16 not in a)
-        self.assertTrue(a not in a)
+            self.assertIn(i, a)
+        self.assertNotIn(16, a)
+        self.assertNotIn(a, a)
 
         a = tuple(a)
         for i in a:
-            self.assertTrue(i in a)
-        self.assertTrue(16 not in a)
-        self.assertTrue(a not in a)
+            self.assertIn(i, a)
+        self.assertNotIn(16, a)
+        self.assertNotIn(a, a)
 
         class Deviant1:
             """Behaves strangely when compared
@@ -86,7 +86,7 @@
                     self.aList.remove(14)
                 return 1
 
-        self.assertTrue(Deviant1() not in Deviant1.aList)
+        self.assertNotIn(Deviant1(), Deviant1.aList)
 
         class Deviant2:
             """Behaves strangely when compared
@@ -99,7 +99,7 @@
                     raise RuntimeError, "gotcha"
 
         try:
-            self.assertTrue(Deviant2() not in a)
+            self.assertNotIn(Deviant2(), a)
         except TypeError:
             pass