use test_main() in __main__ section
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 7b81fc1..95af197 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4207,4 +4207,4 @@
 
 
 if __name__ == '__main__':
-    unittest.main()
+    test_main()