ensure criterion is not None

diff --git a/examples/beaker_caching/meta.py b/examples/beaker_caching/meta.py
index 026d2ce67df118a603ebd4555c82b68fd4ae3279..c5a10c7f7a2d7fe1609cfdf2e01aa32ac7c73145 100644 (file)
--- a/examples/beaker_caching/meta.py
+++ b/examples/beaker_caching/meta.py
@@ -183,7 +183,8 @@ def _params_from_query(query):
             value = value()
             
         v.append(value)
-    visitors.traverse(query._criterion, {}, {'bindparam':visit_bindparam})
+    if query._criterion is not None:
+        visitors.traverse(query._criterion, {}, {'bindparam':visit_bindparam})
     return v
 
 # Beaker CacheManager.  A home base for cache configurations.