# UndefVarError: update\_param! not defined

**URL:** <https://forum.mimiframework.org/t/undefvarerror-update-param-not-defined/144>\
**Category:** Uncategorized\
**Created:** [December 23, 2020, 3:28am UTC](https://forum.mimiframework.org/t/undefvarerror-update-param-not-defined/144 "2020-12-23T03:28:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tammyt123](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/tammyt123/32/81_2.png) [@tammyt123](https://forum.mimiframework.org/u/tammyt123)\
**Post date:** [December 23, 2020, 3:28am UTC](https://forum.mimiframework.org/t/undefvarerror-update-param-not-defined/144/1 "2020-12-23T03:28:32Z")

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Hi there,

I’ve been following the tutorials and was trying to use update\_param! on the MimiFUND model but keep getting the following error:

```
update_param!(m, :climatesensitivity, 5)
ERROR: UndefVarError: update_param! not defined
Stacktrace:
 [1] top-level scope at none:1

```

The only thing that I’ve run before this is:

```
using MimiFUND
m = MimiFUND.get_model()

```

as instructed in the Tutorial. Would appreciate any help! I’ve already tried pkg\> up. Thanks!

---

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**Author:** ![lrennels](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/lrennels/32/6_2.png) [@lrennels](https://forum.mimiframework.org/u/lrennels)\
**Post date:** [December 23, 2020, 11:30pm UTC](https://forum.mimiframework.org/t/undefvarerror-update-param-not-defined/144/2 "2020-12-23T23:30:13Z")

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Hi there,

Have you run `using Mimi` yet? Since `update_param!` is a `Mimi` function, not a `MimiFUND` function, it is not yet in your namespace if you have not run `using Mimi`. As in the readme for `MimiFUND`, I think the steps you are looking for are:

```auto
using Mimi
using MimiFUND

m = MimiFUND.get_model() # Get the default version of the FUND model
set_param!(m, :climatesensitivity, 5) # make any modifications to your model using Mimi
run(m)

# later we can do
update_param!(m, :climatesensitivity, 6) # make any modifications to your model using Mimi

```

Note that since the default MimiFUND model sets the parameter `:climatesensitivity` using the `default` keyword argument, we actually need to use `set_param!` for this first call and then going forward you can modify the model with `update_param!`. This is a complexity we are currently working to remove, and only applies in certain cases where a default is used in model construction instead of an explicit call to `set_param!`.

Lisa

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<div class="post-metadata">

**Author:** ![tammyt123](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.mimiframework.org/tammyt123/32/81_2.png) [@tammyt123](https://forum.mimiframework.org/u/tammyt123)\
**Post date:** [December 24, 2020, 4:46am UTC](https://forum.mimiframework.org/t/undefvarerror-update-param-not-defined/144/3 "2020-12-24T04:46:00Z")

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Thanks so much! I think it’s working now. Much appreciated 🙂