Note change to get_dialect semantics in 2.5. Will backport to 2.5.
diff --git a/Doc/library/csv.rst b/Doc/library/csv.rst
index 98fc6c9..1be909b 100644
--- a/Doc/library/csv.rst
+++ b/Doc/library/csv.rst
@@ -127,6 +127,11 @@
Return the dialect associated with *name*. An :exc:`Error` is raised if *name*
is not a registered dialect name.
+ .. versionchanged:: 2.5
+
+ This function now returns an immutable :class:`Dialect`. Previously an
+ instance of the requested dialect was returned. Users could modify the
+ underlying class, changing the behavior of active readers and writers.
.. function:: list_dialects()