如何在嵌套字典Python/Openerp中调用值

我试图访问嵌套字典中的一个值,并最终得到;

raise ValueError("Invalid field %r in leaf %r" % (left, str(leaf)))
ValueError: Invalid field 'att_date_date' in leaf "<osv.ExtendedLeaf: ('att_date_date', '<=', '2017-08-01') on on_call_days (ctx: )>"

请帮我解决这个问题。我的课堂和其他必要的表达就像贝娄;

on\u call\u天 领域;

'employee_id': fields.many2one('hr.employee', "Employee"),
'catagory_id':fields.related('employee_id', 'category', string='Emp Category', relation='hr.employee',store=True),
'oc_date':fields.date('From Date'),
'oc_amount':fields.float('Amount for the period'),
'processed_flag':fields.boolean("Entered flag"),

Allowment_出席人数 领域;

'employee_id': fields.many2one('hr.employee', "Employee"),
'catagory_id':fields.related('employee_id', 'category', string='Emp Category', relation='hr.employee',store=True),        
'attendance_id':fields.integer("Attendance ID"),
'att_date':fields.char("Date"),
'att_date_date':fields.date("Date Date"),

班 字段,这就是我试图使用这些表达式的类。

    'allowance_attendances_id':fields.one2many('allowance.attendances','allowance_request_id','Allowance Attendance'),
    'oc_days_id':fields.one2many('on.call.days','allowance_request_id','On Call Days'),

我想做的是

   def onchange_employee(self, cr, uid, ids, employee_id,start_date,end_date,context=None):

        DATETIME_FORMAT2 = "%y/%m/%d"
        allo_att_obj=self.pool.get('allowance.attendances')
        on_call_obj=self.pool.get('on.call.days')
        val = {'value': {'allowance_attendances_id': [],'oc_days_id':[]}}
         if end_date:                

                filt +=[('att_date_date','<=', end_date)]            
            if start_date :              

                filt += [('att_date_date','>=', start_date)]

问题来自 filt+=[('att\u date\u date','和lt;=',end\u date)] 我试图从嵌套字典中检索值。请帮助met解决此问题。