inspect.Signature: Add 'Signature.from_callable' classmethod. Closes #17373
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
index c94102d..78bddcb 100644
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -140,6 +140,10 @@
* :class:`inspect.Signature` and :class:`inspect.Parameter` are now
picklable (contributed by Yury Selivanov in :issue:`20726`).
+* New class method :meth:`inspect.Signature.from_callable`, which makes
+ subclassing of :class:`~inspect.Signature` easier (contributed
+ by Yury Selivanov and Eric Snow in :issue:`17373`).
+
Optimizations
=============