ref: a7c01127f9749fe471367c6461cde357403cc3b3
dir: /sys/src/cmd/python/Doc/lib/libconsts.tex/
\section{Built-in Constants} A small number of constants live in the built-in namespace. They are: \begin{datadesc}{False} The false value of the \class{bool} type. \versionadded{2.3} \end{datadesc} \begin{datadesc}{True} The true value of the \class{bool} type. \versionadded{2.3} \end{datadesc} \begin{datadesc}{None} 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}