#15355: Mention already-executing Exception in generator docs.

bitdancer · bitdancer · commit 2c1d1d63100a · 2012-08-17T20:48:59.000-04:00
Patch by Chris Jerdonek.
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
@@ -354,8 +354,15 @@ called, allowing any pending :keyword:`finally` clauses to execute.
 
 .. index:: object: generator
 
-The following generator's methods can be used to control the execution of a
-generator function:
+
+Generator-iterator methods
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This subsection describes the methods of a generator iterator.  They can
+be used to control the execution of a generator function.
+
+Note that calling any of the generator methods below when the generator
+is already executing raises a :exc:`ValueError` exception.
 
 .. index:: exception: StopIteration
 
