diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -231,8 +231,8 @@
 parser = self._get_parser(tester)
 for args_str in tester.failures:
 args = args_str.split()
- raises = tester.assertRaises
- raises(ArgumentParserError, parser.parse_args, args)
+ with tester.assertRaises(ArgumentParserError, msg=args):
+ parser.parse_args(args)
 
 def test_successes(self, tester):
 parser = self._get_parser(tester)
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<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://bugs.python.org/file29280/issue11955.diff">(-&gt;オリジナル)</a>
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