whatsnew: object.__format__ raises TypeError on non-empty string.
See issues #7994 and #9856. I also modified with wording of the format doc
entry to better match what really happens, and added a versionchanged to the
datamodel object.__format__ section.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 4371969..57f015b 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -540,12 +540,13 @@
A call to ``format(value, format_spec)`` is translated to
``type(value).__format__(format_spec)`` which bypasses the instance
dictionary when searching for the value's :meth:`__format__` method. A
- :exc:`TypeError` exception is raised if the method is not found or if either
- the *format_spec* or the return value are not strings.
+ :exc:`TypeError` exception is raised if the method search reaches
+ :mod:`object` and the *format_spec* is non-empty, or if either the
+ *format_spec* or the return value are not strings.
- .. versionadded:: 3.4
+ .. versionchanged:: 3.4
``object().__format__(format_spec)`` raises :exc:`TypeError`
- if *format_spec* is not empty string.
+ if *format_spec* is not an empty string.
.. _func-frozenset: