\ttindex{None}
\obindex{None@{\texttt{None}}}
+\item[NotImplemented]
+This type has a single value. There is a single object with this value.
+This object is accessed through the built-in name \code{NotImplemented}.
+Binary number methods may return this value if they do not implement the
+operation for the types of operands provided. The interpreter will then
+try the reverse operation. Its truth value is true.
+\ttindex{NotImplemented}
+\obindex{NotImplemented@{\texttt{NotImplemented}}}
+
\item[Ellipsis]
This type has a single value. There is a single object with this value.
This object is accessed through the built-in name \code{Ellipsis}.