diff --git a/product/ERP5/Document/Document.py b/product/ERP5/Document/Document.py
index f0a68d5b1d73a40f5b95e727df89e85344829aa0..6a97918bdc14447ad20e9fd8a047e3a33f9c578f 100644
--- a/product/ERP5/Document/Document.py
+++ b/product/ERP5/Document/Document.py
@@ -745,9 +745,10 @@ class Document(PermanentURLMixIn, XMLObject, UrlMixIn, CachedConvertableMixin, S
     """
     if not self.getReference():
       return self
-    catalog = getToolByName(self, 'portal_catalog', None)
+    catalog = getToolByName(self, 'portal_catalog')
     kw = dict(reference=self.getReference(), sort_on=(('version','descending'),))
-    if language is not None: kw['language'] = language
+    if language is not None:
+      kw['language'] = language
     res = catalog(**kw)
 
     original_language = self.getOriginalLanguage()