bpo-31655: Validate keyword names in SimpleNamespace constructor. (#3909)

diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 966ef6d..28133a3 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -1069,6 +1069,8 @@
 
         with self.assertRaises(TypeError):
             types.SimpleNamespace(1, 2, 3)
+        with self.assertRaises(TypeError):
+            types.SimpleNamespace(**{1: 2})
 
         self.assertEqual(len(ns1.__dict__), 0)
         self.assertEqual(vars(ns1), {})