The parameter to the listen() method is not optional, but was marked as
optional in the documentation.
This closes SF bug #427985.
diff --git a/Doc/lib/libasyncore.tex b/Doc/lib/libasyncore.tex
index cce0d50..66998d1 100644
--- a/Doc/lib/libasyncore.tex
+++ b/Doc/lib/libasyncore.tex
@@ -136,7 +136,7 @@
Read at most \var{buffer_size} bytes from the socket.
\end{methoddesc}
-\begin{methoddesc}{listen}{\optional{backlog}}
+\begin{methoddesc}{listen}{backlog}
Listen for connections made to the socket. The \var{backlog}
argument specifies the maximum number of queued connections
and should be at least 1; the maximum value is