Add versionchanged notes for PEP 380
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 7da54a2..9746162 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -355,7 +355,7 @@
garbage collected), the generator-iterator's :meth:`close` method will be
called, allowing any pending :keyword:`finally` clauses to execute.
-When ``yield from expression`` is used, it treats the supplied expression as
+When ``yield from <expr>`` is used, it treats the supplied expression as
a subiterator. All values produced by that subiterator are passed directly
to the caller of the current generator's methods. Any values passed in with
:meth:`send` and any exceptions passed in with :meth:`throw` are passed to
@@ -369,6 +369,9 @@
:exc:`StopIteration`, or automatically when the sub-iterator is a generator
(by returning a value from the sub-generator).
+ .. versionchanged:: 3.3
+ Added ``yield from <expr>`` to delegate control flow to a subiterator
+
The parentheses can be omitted when the :keyword:`yield` expression is the
sole expression on the right hand side of an assignment statement.