-\section{Builtin Constants}
+\section{Built-in Constants}
-A small number of constants live in the builtin namespace. They are:
+A small number of constants live in the built-in namespace. They are:
\begin{datadesc}{False}
-The false value of the \code{bool} type.
-\versionadded{2.3}
+ The false value of the \class{bool} type.
+ \versionadded{2.3}
\end{datadesc}
\begin{datadesc}{True}
-The true value of the \code{bool} type.
-\versionadded{2.3}
+ The true value of the \class{bool} type.
+ \versionadded{2.3}
\end{datadesc}
\begin{datadesc}{None}
-The sole value of \code{NoneType}. \code{None} is frequently used to
-represent the absence of a value, as when default arguments are not passed
-to a function.
+ The sole value of \code{\refmodule{types}.NoneType}. \code{None} is
+ frequently used to represent the absence of a value, as when default
+ arguments are not passed to a function.
\end{datadesc}
+\begin{datadesc}{NotImplemented}
+ Special value which can be returned by the ``rich comparison''
+ special methods (\method{__eq__()}, \method{__lt__()}, and friends),
+ to indicate that the comparison is not implemented with respect to
+ the other type.
+\end{datadesc}
+
+\begin{datadesc}{Ellipsis}
+ Special value used in conjunction with extended slicing syntax.
+ % XXX Someone who understands extended slicing should fill in here.
+\end{datadesc}