Use methoddesc instead of funcdesc to describe the only method.
diff --git a/Doc/lib/libmailbox.tex b/Doc/lib/libmailbox.tex
index 3261217..e9dcb89 100644
--- a/Doc/lib/libmailbox.tex
+++ b/Doc/lib/libmailbox.tex
@@ -30,10 +30,10 @@
All implementations of Mailbox objects have one externally visible
method:
-\begin{funcdesc}{next}{}
+\begin{methoddesc}[mailbox]{next}{}
Return the next message in the mailbox, as a \class{rfc822.Message} object.
Depending on the mailbox implementation the \var{fp} attribute of this
object may be a true file object or a class instance simulating a file object,
taking care of things like message boundaries if multiple mail messages are
contained in a single file, etc.
-\end{funcdesc}
+\end{methoddesc}
diff --git a/Doc/libmailbox.tex b/Doc/libmailbox.tex
index 3261217..e9dcb89 100644
--- a/Doc/libmailbox.tex
+++ b/Doc/libmailbox.tex
@@ -30,10 +30,10 @@
All implementations of Mailbox objects have one externally visible
method:
-\begin{funcdesc}{next}{}
+\begin{methoddesc}[mailbox]{next}{}
Return the next message in the mailbox, as a \class{rfc822.Message} object.
Depending on the mailbox implementation the \var{fp} attribute of this
object may be a true file object or a class instance simulating a file object,
taking care of things like message boundaries if multiple mail messages are
contained in a single file, etc.
-\end{funcdesc}
+\end{methoddesc}