Fix-up __reduce__ which could not reach the __keys variable indirectly.'
diff --git a/Lib/collections.py b/Lib/collections.py
index 4028983..a1e8ed9 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -58,9 +58,13 @@
def __reduce__(self):
items = [[k, self[k]] for k in self]
+ tmp = self.__keys
+ del self.__keys
inst_dict = vars(self).copy()
- inst_dict.pop('__keys', None)
- return (self.__class__, (items,), inst_dict)
+ self.__keys = tmp
+ if inst_dict:
+ return (self.__class__, (items,), inst_dict)
+ return self.__class__, (items,)
setdefault = MutableMapping.setdefault
update = MutableMapping.update