diff -r a8df1ca60452 Lib/types.py
--- a/Lib/types.py	Mon Feb 23 00:31:33 2015 +0200
+++ b/Lib/types.py	Tue Feb 24 00:12:52 2015 +0200
@@ -156,3 +156,6 @@ class DynamicClassAttribute:
         result = type(self)(self.fget, self.fset, fdel, self.__doc__)
         result.overwrite_doc = self.overwrite_doc
         return result
+
+
+__all__ = [n for n in globals() if n[:1] != '_']