Revert r79179 and merge r75584 to explain how to implement a queue using collection.deque instead of a list.
Revert r79179 and merge r75584 to explain how to implement a queue using collection.deque instead of a list.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator