# A good example on Param class usage with dependable selectors

**URL:** <https://discourse.holoviz.org/t/a-good-example-on-param-class-usage-with-dependable-selectors/1563>\
**Category:** Panel\
**Tags:** param\
**Created:** [December 14, 2020, 8:03pm UTC](https://discourse.holoviz.org/t/a-good-example-on-param-class-usage-with-dependable-selectors/1563 "2020-12-14T20:03:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AntonBiryukovUofC](https://discourse.holoviz.org/user_avatar/discourse.holoviz.org/antonbiryukovuofc/32/2308_2.png) [@AntonBiryukovUofC](https://discourse.holoviz.org/u/AntonBiryukovUofC)\
**Post date:** [December 14, 2020, 8:03pm UTC](https://discourse.holoviz.org/t/a-good-example-on-param-class-usage-with-dependable-selectors/1563/1 "2020-12-14T20:03:53Z")

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Hello folks, apologies for what potentially is a dumb question. I really appreciate awesome-panel resource created by @Marc and was wondering, if there was a good example somewhere on power usage of dashboard classes inherited from Parameterized. SPecifically, I am looking for examples where one parameter (selector) affects the choices in another parameter (selector)

I have seen the example in the Documentation, however I have a feeling it underused the Param functionality. I feel like it would be much cleaner to specify something like this:

```auto
versions_default = ['a','b','c']
class ReactiveDashboard(param.Parameterized):

    versions = param.List(default=versions_default)
    config_version = param.ObjectSelector(label='Config version',
                                     objects=versions
                                     default=versions[-1])

```

instead of updating `param['config_version'].objects` property directly in a separate watch function without necessarily storing that objects list in a tidy container.

Any advice / pointers will be appreciated.

Thanks.

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**Author:** ![Marc](https://discourse.holoviz.org/user_avatar/discourse.holoviz.org/marc/32/24_2.png) [@Marc](https://discourse.holoviz.org/u/Marc)\
**Post date:** [December 15, 2020, 4:14am UTC](https://discourse.holoviz.org/t/a-good-example-on-param-class-usage-with-dependable-selectors/1563/2 "2020-12-15T04:14:45Z")

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Hi @AntonBiryukovUofC

Welcome to the community. I’m not sure I totally understand what you are trying to solve 🙂 But maybe the `Selector` instead of `ObjectSelector` is what you are looking for?

 ![image](https://discourse.holoviz.org/uploads/default/original/2X/9/9d21b70592e1db76882d61eda3a5d90d42cb0ea0.png)