Add count() method to collections.deque().
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 5a6f0de..f4ba51a 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -358,6 +358,12 @@
Remove all elements from the deque leaving it with length 0.
+ .. method:: count(x)
+
+ Count the number of deque elements equal to *x*.
+
+ .. versionadded:: 2.7
+
.. method:: extend(iterable)
Extend the right side of the deque by appending elements from the iterable