# Assert isinstance(value, (Model, type(None))

**URL:** <https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834>\
**Category:** Developer\
**Created:** [October 15, 2019, 5:48am UTC](https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834 "2019-10-15T05:48:13Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![prashasti.sharma](https://discuss-cdn.tryton.org/letter_avatar_proxy/v4/letter/p/58f4c7/32.png) [@prashasti.sharma](https://discuss.tryton.org/u/prashasti.sharma)\
**Post date:** [October 15, 2019, 5:48am UTC](https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834/1 "2019-10-15T05:48:13Z")

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Sir, the previous error is resolved but, assertion error is coming. How to solve it.

 ![Screenshot%20from%202019-10-15%2011-14-09](https://discuss-cdn.tryton.org/uploads/default/original/1X/734e079f2ad19726b1300a94f7f21f6aa2c4645c.png)

```auto
Preformatted te
======================
Hr_Hra Replace Scenario
======================

Imports::

    >>> from proteus import Model, Wizard
    >>> from trytond.tests.tools import activate_modules
    >>> from trytond.modules.company.tests.tools import create_company
    
Install hr_hra::

    >>> config = activate_modules('hr_hra')

Create a employee::
    >>> company = create_company()
    >>> employee = Model.get('company.employee')
    >>> party = Model.get('party.party')
    >>> party_cur = party(name='Prashasti')
    >>> party_cur.save()
    >>> employee1 = employee(company=company,
    ... party=party_cur,
    ... employee_group='A',
    ... employee_status='Regular',
    ... primary_phone='9935164850',
    ...	)
    >>> employee1.save()
   xt

```

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<div class="post-metadata">

**Author:** ![ced](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/ced/32/1237_2.png) [@ced](https://discuss.tryton.org/u/ced)\
**Post date:** [October 15, 2019, 6:58am UTC](https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834/2 "2019-10-15T06:58:31Z")

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It seems you are assigned a value that is not from the proper type.  
I guess it is the `employee_group` which should probably be a `res.group` instance and not a string.

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<div class="post-metadata">

**Author:** ![prashasti.sharma](https://discuss-cdn.tryton.org/letter_avatar_proxy/v4/letter/p/58f4c7/32.png) [@prashasti.sharma](https://discuss.tryton.org/u/prashasti.sharma)\
**Post date:** [October 15, 2019, 7:06am UTC](https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834/3 "2019-10-15T07:06:34Z")

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Sir, employee\_group is a Selection field

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<div class="post-metadata">

**Author:** ![ced](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/ced/32/1237_2.png) [@ced](https://discuss.tryton.org/u/ced)\
**Post date:** [October 15, 2019, 7:11am UTC](https://discuss.tryton.org/t/assert-isinstance-value-model-type-none/1834/4 "2019-10-15T07:11:13Z")

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Well one of them is a Many2One for which you put a string. I do not know which one of your custom field.