--- a/piecrust/data/provider.py	Sat Aug 16 08:15:30 2014 -0700
+++ b/piecrust/data/provider.py	Sat Aug 16 15:07:22 2014 -0700
@@ -1,5 +1,4 @@
 import time
-import itertools
 from piecrust.data.iterators import PageIterator
 from piecrust.sources.base import ArraySource
 
@@ -18,7 +17,10 @@
 
     def __getattr__(self, name):
         if self._user_data is not None:
-            return self._user_data[name]
+            try:
+                return self._user_data[name]
+            except KeyError:
+                pass
         raise AttributeError()
 
     def __getitem__(self, name):
@@ -170,6 +172,8 @@
         for fac in self._source.getPageFactories():
             post = fac.buildPage()
             tax_values = post.config.get(tax_name)
+            if tax_values is None:
+                continue
             if not isinstance(tax_values, list):
                 tax_values = [tax_values]
             for val in tax_values: