Create the dbm package from PEP 3108. #2881.
diff --git a/Lib/io.py b/Lib/io.py
index 207e428..0c993b1 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -270,7 +270,7 @@
     """Wrapper for builtins.open
 
     Trick so that open won't become a bound method when stored
-    as a class variable (as dumbdbm does).
+    as a class variable (as dbm.dumb does).
 
     See initstdio() in Python/pythonrun.c.
     """