Add count() method to collections.deque().
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index aa17a55..3d04063 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -338,6 +338,12 @@
Remove all elements from the deque leaving it with length 0.
+ .. method:: count(x)
+
+ Count the number of deque elements equal to *x*.
+
+ .. versionadded:: 3.2
+
.. method:: extend(iterable)
Extend the right side of the deque by appending elements from the iterable