add a minimal docstring and remove unsuded imports

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@28028 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/BudgetCell.py

@@ -33,13 +33,8 @@ from Products.ERP5Type import Permissions, PropertySheet, Constraint, interfaces
 from Products.ERP5.Document.Predicate import Predicate
 from Products.ERP5.Document.MetaNode import MetaNode
 
-from Products.ERP5.Document.InventoryCell import InventoryCell
-
-from zLOG import LOG
-
 class BudgetCell(Predicate, MetaNode):
-    """
-    BudgetCell ...
+    """ Budget Cell defines a cell of budget.
     """
 
     # Default Properties