use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_funcattrs.py b/Lib/test/test_funcattrs.py
index 96a1018..b639ca2 100644
--- a/Lib/test/test_funcattrs.py
+++ b/Lib/test/test_funcattrs.py
@@ -68,7 +68,7 @@
         a = 12
         def f(): print a
         c = f.func_closure
-        self.assertTrue(isinstance(c, tuple))
+        self.assertIsInstance(c, tuple)
         self.assertEqual(len(c), 1)
         # don't have a type object handy
         self.assertEqual(c[0].__class__.__name__, "cell")