\section{\module{whichdb} ---
         Guess which DBM module created a database}

\declaremodule{standard}{whichdb}
\modulesynopsis{Guess which DBM-style module created a given database.}


The single function in this module attempts to guess which of the
several simple database modules available--\refmodule{dbm},
\refmodule{gdbm}, or \refmodule{dbhash}--should be used to open a
given file.

\begin{funcdesc}{whichdb}{filename}
Returns one of the following values: \code{None} if the file can't be
opened because it's unreadable or doesn't exist; the empty string
(\code{''}) if the file's format can't be guessed; or a string
containing the required module name, such as \code{'dbm'} or
\code{'gdbm'}.
\end{funcdesc}