partner_obj = self.pool.get('res.partner')
today = date.today()
ids = partner_obj.search(cr, uid, [('membership_state', '=', 'paid'), ('membership_stop', '<', today)], context=None)
partner_obj = self.pool.get('res.partner')
today = date.today()
ids = partner_obj.search(cr, uid, [('membership_state', '=', 'paid'), ('membership_stop', '<', today)], context=None)