use assert[Not]In where appropriate
diff --git a/Lib/test/test_xrange.py b/Lib/test/test_xrange.py
index 9268c76..49f4851 100644
--- a/Lib/test/test_xrange.py
+++ b/Lib/test/test_xrange.py
@@ -63,18 +63,18 @@
         self.assertEqual(list(xrange(a+4, a, -2)), [a+4, a+2])
 
         seq = list(xrange(a, b, c))
-        self.assertTrue(a in seq)
-        self.assertTrue(b not in seq)
+        self.assertIn(a, seq)
+        self.assertNotIn(b, seq)
         self.assertEqual(len(seq), 2)
 
         seq = list(xrange(b, a, -c))
-        self.assertTrue(b in seq)
-        self.assertTrue(a not in seq)
+        self.assertIn(b, seq)
+        self.assertNotIn(a, seq)
         self.assertEqual(len(seq), 2)
 
         seq = list(xrange(-a, -b, -c))
-        self.assertTrue(-a in seq)
-        self.assertTrue(-b not in seq)
+        self.assertIn(-a, seq)
+        self.assertNotIn(-b, seq)
         self.assertEqual(len(seq), 2)
 
         self.assertRaises(TypeError, xrange)