datetime not working in xml

I am using OpenERP-7.0 and Ubuntu-10.04. Following code is working fine in 6.0 & 6.1 but it's giving error in 7.0 Here is my code: Leaves to be Accountedir.actions.act_windowhr.holidaysformtree,form[('date_from','>=',(datetime.date.today()-relativedelta(weeks=1)).strftime('%Y-%m-%d'))] I am facing following error: `7.0/server/openerp/tools/safe_eval.py", line 241, in safe_eval return eval(test_expr(expr, _SAFE_OPCODES, mode=mode), globals_dict, locals_dict) File "", line 1, in NameError: name 'datetime' is not defined` I tried **DateTime** also, but it's not working. Can anyone please help me? Thanks in advance.