Index: newforms/models.py
===================================================================
--- newforms/models.py	(revision 5822)
+++ newforms/models.py	(working copy)
@@ -123,7 +123,7 @@
     return type('FormForFields', (BaseForm,), {'base_fields': fields})
 
 class QuerySetIterator(object):
-    def __init__(self, queryset, empty_label, cache_choices):
+    def __init__(self, queryset, empty_label=None, cache_choices=None):
         self.queryset, self.empty_label, self.cache_choices = queryset, empty_label, cache_choices
 
     def __iter__(self):