diff -r 62438d1b11c7 Lib/_collections_abc.py
--- a/Lib/_collections_abc.py	Fri May 02 23:26:03 2014 +0200
+++ b/Lib/_collections_abc.py	Fri May 02 20:09:21 2014 -0400
@@ -440,6 +440,8 @@
 
 class MappingView(Sized):
 
+    __slots__ = '_mapping',
+
     def __init__(self, mapping):
         self._mapping = mapping
 
@@ -452,6 +454,8 @@
 
 class KeysView(MappingView, Set):
 
+    __slots__ = ()
+
     @classmethod
     def _from_iterable(self, it):
         return set(it)
@@ -467,6 +471,8 @@
 
 class ItemsView(MappingView, Set):
 
+    __slots__ = ()
+
     @classmethod
     def _from_iterable(self, it):
         return set(it)
@@ -489,6 +495,8 @@
 
 class ValuesView(MappingView):
 
+    __slots__ = ()
+
     def __contains__(self, value):
         for key in self._mapping:
             if value == self._mapping[key]: