Get rid of dict.has_key(). Boy this has a lot of repercussions!
Not all code has been fixed yet; this is just a checkpoint...
The C API still has PyDict_HasKey() and _HasKeyString(); not sure
if I want to change those just yet.
diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index 6ee9e2c..93cadd7 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -660,7 +660,7 @@
     def __init__(self, proxies=None):
         if proxies is None:
             proxies = getproxies()
-        assert hasattr(proxies, 'has_key'), "proxies must be a mapping"
+        assert hasattr(proxies, 'keys'), "proxies must be a mapping"
         self.proxies = proxies
         for type, url in proxies.items():
             setattr(self, '%s_open' % type,