- PEP 3106: dict.iterkeys(), .iteritems(), .itervalues() are now gone;
  and .keys(), .items(), .values() return dict views.

The dict views aren't fully functional yet; in particular, they can't
be compared to sets yet.  but they are useful as "iterator wells".

There are still 27 failing unit tests; I expect that many of these
have fairly trivial fixes, but there are so many, I could use help.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 8c636c1..c4b7d37 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -437,18 +437,18 @@
 
     def keys(self):
         """Get all of a message's header field names."""
-        return self.dict.keys()
+        return list(self.dict.keys())
 
     def values(self):
         """Get all of a message's header field values."""
-        return self.dict.values()
+        return list(self.dict.values())
 
     def items(self):
         """Get all of a message's headers.
 
         Returns a list of name, value tuples.
         """
-        return self.dict.items()
+        return list(self.dict.items())
 
     def __str__(self):
         return ''.join(self.headers)