Fix #15567. collections.deque wasn't imported
diff --git a/Lib/threading.py b/Lib/threading.py
index 2290855..db9ab29 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -10,6 +10,7 @@
 
 import warnings
 
+from collections import deque as _deque
 from time import time as _time, sleep as _sleep
 from traceback import format_exc as _format_exc
 
@@ -913,7 +914,7 @@
             self.rc = Condition(self.mon)
             self.wc = Condition(self.mon)
             self.limit = limit
-            self.queue = deque()
+            self.queue = _deque()
 
         def put(self, item):
             self.mon.acquire()