Issue #7264: Fix a possible deadlock when deallocating thread-local objects
which are part of a reference cycle.
diff --git a/Lib/threading.py b/Lib/threading.py
index cf20152..9ad5122 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -810,6 +810,10 @@
 
 active_count = activeCount
 
+def _enumerate():
+    # Same as enumerate(), but without the lock. Internal use only.
+    return _active.values() + _limbo.values()
+
 def enumerate():
     with _active_limbo_lock:
         return _active.values() + _limbo.values()