[Python-checkins] bpo-42179: Doc/tutorial: Remove mention of __cause__ (GH-23162)

[miss-islington]

https://github.com/python/cpython/commit/e74fb2d7666eea43ad738528a565bb56bc88c28d
commit: e74fb2d7666eea43ad738528a565bb56bc88c28d
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2020-11-05T19:05:57-08:00
summary:

bpo-42179: Doc/tutorial: Remove mention of __cause__ (GH-23162)

(cherry picked from commit bde33e428d5b5f88ec7667598fd27d1091840537)

Co-authored-by: Inada Naoki <songofacandy at gmail.com>

files:
M Doc/tutorial/errors.rst

diff --git a/Doc/tutorial/errors.rst b/Doc/tutorial/errors.rst
index 0ce96466e8c28..efe44da3043c5 100644
--- a/Doc/tutorial/errors.rst
+++ b/Doc/tutorial/errors.rst
@@ -273,15 +273,15 @@ Exception Chaining
 ==================
 
 The :keyword:`raise` statement allows an optional :keyword:`from` which enables
-chaining exceptions by setting the ``__cause__`` attribute of the raised
-exception. For example::
+chaining exceptions. For example::
 
-    raise RuntimeError from OSError
+    # exc must be exception instance or None.
+    raise RuntimeError from exc
 
 This can be useful when you are transforming exceptions. For example::
 
     >>> def func():
-    ...    raise IOError
+    ...     raise IOError
     ...
     >>> try:
     ...     func()
@@ -297,12 +297,11 @@ This can be useful when you are transforming exceptions. For example::
     <BLANKLINE>
     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
-    RuntimeError
+    RuntimeError: Failed to open database
 
-The expression following the :keyword:`from` must be either an exception or
-``None``. Exception chaining happens automatically when an exception is raised
-inside an exception handler or :keyword:`finally` section. Exception chaining
-can be disabled by using ``from None`` idiom:
+Exception chaining happens automatically when an exception is raised inside an
+:keyword:`except` or :keyword:`finally` section. Exception chaining can be
+disabled by using ``from None`` idiom:
 
     >>> try:
     ...     open('database.sqlite')
@@ -313,6 +312,8 @@ can be disabled by using ``from None`` idiom:
       File "<stdin>", line 4, in <module>
     RuntimeError
 
+For more information about chaining mechanics, see :ref:`bltin-exceptions`.
+
 
 .. _tut-userexceptions: