\begin{methoddesc}{uidl}{\optional{which}}
Return message digest (unique id) list.
-If \var{which} is specified, result contains unique id for that
-message, otherwise result is list \code{['response',
-['mesgnum uid', ...], octets]}.
+If \var{which} is specified, result contains the unique id for that
+message in the form \code{'\var{response}\ \var{mesgnum}\ \var{uid}},
+otherwise result is list \code{['response', ['mesgnum uid', ...], octets]}.
\end{methoddesc}