Implementation of PEP-0217.
This closes the PEP, and patch 103170
diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index 2fda26e..df32182 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -44,6 +44,15 @@
 Availability: Windows.
 \end{datadesc}
 
+\begin{funcdesc}{displayhook}{\var{value}}
+If \var{value} is not \code{None}, this function prints it to 
+\code{sys.stdout}, and saves it in \code{__builtin__._}.
+
+This function is called when an expression is entered at the prompt
+of an interactive Python session. It exists mainly so it can be
+overridden.
+\end{funcdesc}
+
 \begin{funcdesc}{exc_info}{}
 This function returns a tuple of three values that give information
 about the exception that is currently being handled.  The information