Fixed missing parent access.

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@36058 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/mixin/explainable.py

@@ -96,6 +96,8 @@ class ExplainableMixin:
             # Make sure not to include same delivery twice
             result.append(delivery_or_item)
 
+      document = document.getParentValue()
+
     return result
 
   security.declareProtected(Permissions.AccessContentsInformation,'getRootExplanationValue')