logging: made _handlers a WeakValueDictionary.
diff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
index f5dfc39..b1f92b0 100644
--- a/Lib/logging/__init__.py
+++ b/Lib/logging/__init__.py
@@ -590,7 +590,7 @@
# Handler classes and functions
#---------------------------------------------------------------------------
-_handlers = {} #map of handler names to handlers
+_handlers = weakref.WeakValueDictionary() #map of handler names to handlers
_handlerList = [] # added to allow handlers to be removed in reverse of order initialized
def _removeHandlerRef(wr):