:mod:`whichdb` --- Guess which DBM module created a database

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.. module:: whichdb

   :synopsis: Guess which DBM-style module created a given database.

.. note::

   The :mod:`whichdb` module's only function has been put into the :mod:`dbm`

   module in Python 3.0.  The :term:`2to3` tool will automatically adapt imports

   when converting your sources to 3.0.

The single function in this module attempts to guess which of the several simple

database modules available--\ :mod:`dbm`, :mod:`gdbm`, or :mod:`dbhash`\

--should be used to open a given file.

.. function:: whichdb(filename)

   Returns one of the following values: ``None`` if the file can't be opened

   because it's unreadable or doesn't exist; the empty string (``''``) if the

   file's format can't be guessed; or a string containing the required module name,

   such as ``'dbm'`` or ``'gdbm'``.