Make test class name unique so that both test classes run.
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 74075bb..2f2dd4d 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4259,7 +4259,7 @@
 # ArgumentTypeError tests
 # =======================
 
-class TestArgumentError(TestCase):
+class TestArgumentTypeError(TestCase):
 
     def test_argument_type_error(self):