Issue #19288: Fixed the "in" operator of dbm.gnu databases for string
argument.  Original patch by Arfrever Frehtes Taifersar Arahesis.
diff --git a/Lib/test/test_dbm_gnu.py b/Lib/test/test_dbm_gnu.py
index bf62946..4fb66c5 100755
--- a/Lib/test/test_dbm_gnu.py
+++ b/Lib/test/test_dbm_gnu.py
@@ -24,6 +24,7 @@
         self.g[b'bytes'] = b'data'
         key_set = set(self.g.keys())
         self.assertEqual(key_set, set([b'a', b'bytes', b'12345678910']))
+        self.assertIn('a', self.g)
         self.assertIn(b'a', self.g)
         self.assertEqual(self.g[b'bytes'], b'data')
         key = self.g.firstkey()