# Purpose of qml variable definition on the code

**URL:** <https://discuss.pennylane.ai/t/purpose-of-qml-variable-definition-on-the-code/9420>\
**Category:** Codebook\
**Created:** [July 24, 2026, 2:07am UTC](https://discuss.pennylane.ai/t/purpose-of-qml-variable-definition-on-the-code/9420 "2026-07-24T02:07:51Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mbzadegan](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/mbzadegan/32/4298_2.png) [@mbzadegan](https://discuss.pennylane.ai/u/mbzadegan)\
**Post date:** [July 24, 2026, 2:07am UTC](https://discuss.pennylane.ai/t/purpose-of-qml-variable-definition-on-the-code/9420/1 "2026-07-24T02:07:51Z")

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Hello all,

What is the reason for defining the **qml** variable in the following program on [this page](https://pennylane.ai/codebook/introduction-to-quantum-computing/quantum-circuits)?

 ![Screenshot 2026-07-23 6.50.42 PM](https://canada1.discourse-cdn.com/flex012/uploads/pennylane/original/2X/c/cd74cb3a878aa49c1194c96c6bf934c64205c16f.jpeg)

Thank you 🙏

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**Author:** ![CatalinaAlbornoz](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/catalinaalbornoz/32/1196_2.png) [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Post date:** [July 24, 2026, 8:51pm UTC](https://discuss.pennylane.ai/t/purpose-of-qml-variable-definition-on-the-code/9420/2 "2026-07-24T20:51:09Z")

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Hi @mbzadegan , this looks like a mistake in the Codebook. Thanks for reporting this! We’ll make sure to fix this.

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<div class="post-metadata">

**Author:** ![mbzadegan](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/mbzadegan/32/4298_2.png) [@mbzadegan](https://discuss.pennylane.ai/u/mbzadegan)\
**Post date:** [October 11, 2026, 1:23am UTC](https://discuss.pennylane.ai/t/purpose-of-qml-variable-definition-on-the-code/9420/3 "2026-10-11T01:23:37Z")

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Hi Catalina,

Thank you again for confirming this issue.

I’m interested in contributing directly to PennyLane and helping fix Codebook issues through GitHub Pull Requests.

Since the original Codebook repository has been archived, could you please let me know whether the current Codebook source is publicly available and where I should submit a PR for Codebook correction?

I’d be happy to prepare the fix myself.

BTW, I think that it is most useful to show the related Quantum Circuit (Which has been attached) before or after the Pennylane code:

 ![Screenshot_20261011_132653](https://canada1.discourse-cdn.com/flex012/uploads/pennylane/original/2X/f/f58bcaf88ff2f748e40b75f4ea249db352ebfc0a.png)

Thanks!