Fix argument name in reST doc to match the code
diff --git a/Doc/library/dbm.rst b/Doc/library/dbm.rst
index c7c7347..cbefc1a 100644
--- a/Doc/library/dbm.rst
+++ b/Doc/library/dbm.rst
@@ -30,9 +30,9 @@
name, such as ``'dbm.ndbm'`` or ``'dbm.gnu'``.
-.. function:: open(filename, flag='r', mode=0o666)
+.. function:: open(file, flag='r', mode=0o666)
- Open the database file *filename* and return a corresponding object.
+ Open the database file *file* and return a corresponding object.
If the database file already exists, the :func:`whichdb` function is used to
determine its type and the appropriate module is used; if it does not exist,