use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_sysconfig.py b/Lib/test/test_sysconfig.py
index d323222..efbfe97 100644
--- a/Lib/test/test_sysconfig.py
+++ b/Lib/test/test_sysconfig.py
@@ -105,7 +105,7 @@
 
     def test_get_config_vars(self):
         cvars = get_config_vars()
-        self.assertTrue(isinstance(cvars, dict))
+        self.assertIsInstance(cvars, dict)
         self.assertTrue(cvars)
 
     def test_get_platform(self):