Issue #20624: Merge exception docs tweak from 3.4 branch.
diff --git a/Doc/library/exceptions.rst b/Doc/library/exceptions.rst
index 9943b9a..9291c18 100644
--- a/Doc/library/exceptions.rst
+++ b/Doc/library/exceptions.rst
@@ -38,10 +38,10 @@
interpreter raises the same exception; but beware that there is nothing to
prevent user code from raising an inappropriate error.
-The built-in exception classes can be sub-classed to define new exceptions;
-programmers are encouraged to at least derive new exceptions from the
-:exc:`Exception` class and not :exc:`BaseException`. More information on
-defining exceptions is available in the Python Tutorial under
+The built-in exception classes can be subclassed to define new exceptions;
+programmers are encouraged to derive new exceptions from the :exc:`Exception`
+class or one of its subclasses, and not from :exc:`BaseException`. More
+information on defining exceptions is available in the Python Tutorial under
:ref:`tut-userexceptions`.
The following exceptions are only used as base classes for other exceptions.