diff --git a/product/ERP5/Document/BusinessTemplate.py b/product/ERP5/Document/BusinessTemplate.py
index 2616258ef62557556882036ab2fec13e8dd50936..31918a80ddb5a0386a6e1a0d0d67fc4783f54cfc 100755
--- a/product/ERP5/Document/BusinessTemplate.py
+++ b/product/ERP5/Document/BusinessTemplate.py
@@ -361,6 +361,7 @@ Une ligne tarifaire."""
       ordered list
       """
       result = getattr(self,'template_catalog_method_id',())
+      if result is None: result = ()
       if result != ():
         result = list(result)
         result.sort()