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/wsgiref/validate.py b/Lib/wsgiref/validate.py
index 23ab9f8..43784f9 100644
--- a/Lib/wsgiref/validate.py
+++ b/Lib/wsgiref/validate.py
@@ -345,7 +345,7 @@
             "Invalid CONTENT_LENGTH: %r" % environ['CONTENT_LENGTH'])
 
     if not environ.get('SCRIPT_NAME'):
-        assert_(environ.has_key('PATH_INFO'),
+        assert_('PATH_INFO' in environ,
             "One of SCRIPT_NAME or PATH_INFO are required (PATH_INFO "
             "should at least be '/' if SCRIPT_NAME is empty)")
     assert_(environ.get('SCRIPT_NAME') != '/',