diff --git a/product/ERP5Type/XMLMatrix.py b/product/ERP5Type/XMLMatrix.py
index b2dffe77c2dc9396a2cedb3c5e2a0ff48541445f..d5604db0643eeef9b2b38b2c862db8f50220cca2 100644
--- a/product/ERP5Type/XMLMatrix.py
+++ b/product/ERP5Type/XMLMatrix.py
@@ -488,7 +488,7 @@ class XMLMatrix(Folder):
       """
       if getattr(aq_base(self), 'index', None) is None:
         return None
-      base_id= kwd.get('base_id', "cell")
+      base_id = kwd.get('base_id', "cell")
       cell_id = base_id
       if not self.index.has_key(cell_id):
         return None