Odoo安装应用程序，错误：AttributeError：'NoneType'对象没有属性'id'

Question

ps：odoo version 9.0

Odoo Server Erro

Odoo Server Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/openerp/http.py", line 648, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/usr/lib/python2.7/dist-packages/openerp/http.py", line 685, in dispatch
．．．．．．．．．．．．．．．
    return api.model(lambda model: field.convert_to_write(value(model)))
File "/usr/lib/python2.7/dist-packages/openerp/fields.py", line 1719, in convert_to_write
    return value.id
AttributeError: 'NoneType' object has no attribute 'id'

安装系统app，这个错误，都一样。我需要你的帮助