Unnecessary import removed

diff --git a/tornado/stack_context.py b/tornado/stack_context.py
index 14478c1d9423cb83005dc733e4454540c4a7bc6e..f52350e9d07a8c03d7d8d448e5e4d6033800feb0 100644 (file)
--- a/tornado/stack_context.py
+++ b/tornado/stack_context.py
@@ -73,8 +73,6 @@ import sys
 import threading
 import operator
 
-from collections import deque
-
 from tornado.util import raise_exc_info