bpo-41810: Reintroduce `types.EllipsisType`, `.NoneType` & `.NotImplementedType` (GH-22336)
closes issue 41810
diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst
index f17e1a3..38dd552 100644
--- a/Doc/library/constants.rst
+++ b/Doc/library/constants.rst
@@ -19,19 +19,21 @@
.. data:: None
- The sole value of the type ``NoneType``. ``None`` is frequently used to
- represent the absence of a value, as when default arguments are not passed to a
- function. Assignments to ``None`` are illegal and raise a :exc:`SyntaxError`.
+ An object frequently used to represent the absence of a value, as when
+ default arguments are not passed to a function. Assignments to ``None``
+ are illegal and raise a :exc:`SyntaxError`.
+ ``None`` is the sole instance of the :data:`NoneType` type.
.. data:: NotImplemented
- Special value which should be returned by the binary special methods
+ A special value which should be returned by the binary special methods
(e.g. :meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, :meth:`__rsub__`,
etc.) to indicate that the operation is not implemented with respect to
the other type; may be returned by the in-place binary special methods
(e.g. :meth:`__imul__`, :meth:`__iand__`, etc.) for the same purpose.
It should not be evaluated in a boolean context.
+ ``NotImplemented`` is the sole instance of the :data:`types.NotImplementedType` type.
.. note::
@@ -59,8 +61,9 @@
.. index:: single: ...; ellipsis literal
.. data:: Ellipsis
- The same as the ellipsis literal "``...``". Special value used mostly in conjunction
+ The same as the ellipsis literal "``...``". Special value used mostly in conjunction
with extended slicing syntax for user-defined container data types.
+ ``Ellipsis`` is the sole instance of the :data:`types.EllipsisType` type.
.. data:: __debug__