use assert[Not]In where appropriate
diff --git a/Lib/test/test_dbm.py b/Lib/test/test_dbm.py
index 2008776..78357a0 100644
--- a/Lib/test/test_dbm.py
+++ b/Lib/test/test_dbm.py
@@ -93,7 +93,7 @@
         self.init_db()
         f = dbm.open(_fname, 'r')
         key = "a".encode("ascii")
-        assert(key in f)
+        self.assertIn(key, f)
         assert(f[key] == b"Python:")
         f.close()