# \`@mtkmodel\` & \`constants\`?

**URL:** https://discourse.julialang.org/t/mtkmodel-constants/106955
**Category:** Modelling & Simulations
**Created:** [November 30, 2023, 2:31pm UTC](https://discourse.julialang.org/t/mtkmodel-constants/106955 "2023-11-30T14:31:18Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![BLI](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bli/32/37206_2.png) [@BLI](https://discourse.julialang.org/u/BLI)
#### Post date: [November 30, 2023, 2:31pm UTC](https://discourse.julialang.org/t/mtkmodel-constants/106955/1 "2023-11-30T14:31:18Z")

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I’m using ModelingToolkit v8.73.1.

I’m trying to use `@constants` with a `begin...end` construct within an MTK model created by `@mtkmodel` [similar to using a `@parameters` construct], but Julia tells me that `@constants` is not supported.

_Questions_:

- Isn’t there a `@constants` macro within MTK? If yes, is it just that it doesn’t work with `@mtkmodel`?
- Is this a design choice, or is the plan to add support for `@constants` at a later stage?