# PyCyphal + Datatypes with intellisense/Pylance

**URL:** <https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430>\
**Category:** Applications & Usage\
**Created:** [November 18, 2025, 11:06am UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430 "2025-11-18T11:06:20Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Scoeerg](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/scoeerg/32/1713_2.png) [@Scoeerg](https://forum.opencyphal.org/u/Scoeerg)\
**Post date:** [November 18, 2025, 11:06am UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430/1 "2025-11-18T11:06:20Z")

</div>

Hi,

Given a transpiled python-package of e.g. `public_regulated_datatypes` and some intellisense/Pylance in a given IDE (in my case VSCode) there is a mismatch between what Intellisense believes is true and run-time behavior.

I install all my python-packages into:  
`install/my_project/local/lib/python3.10/dist-packages/`

including `/install/my_project/local/lib/python3.10/dist-packages/uavcan`. Now intellisense gets that information:

```auto
// .vscode/settings.json
"python.autoComplete.extraPaths": [
        "${workspaceFolder}/install/my_project/local/lib/python3.10/dist-packages"
],

```

Now, I start coding e.g.:

```auto
import uavcan.node.Heartbeat_1_0
self.heartbeat_sub = self.pycyphal_node.make_subscriber(
            uavcan.node.Heartbeat_1_0,
            uavcan.node.Heartbeat_1_0._FIXED_PORT_ID_
        )

```

which works. But intellisense believes that’s not correct, since there is no such thing as `uavcan.node.Heartbeat_1_0._FIXED_PORT_ID_` but rather it believes it should be `uavcan.node.Heartbeat_1_0.Heartbeat_1_0._FIXED_PORT_ID_`. At run-time the “intellisense-way” will fail. Am I an idiot, or is there something wrong? Is there a proper way to solve this?

This behavior is exemplary for all message-types and attributes. e.g.:

- `uavcan.node.Mode_1_0.OPERATIONAL` and `uavcan.node.Mode_1_0.Mode_1_0.OPERATIONAL`
- `uavcan.register.Access_1_0.Response` and `uavcan.register.Access_1_0.Access_1_0.Response`  
…

---

<div class="post-metadata">

**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [November 18, 2025, 11:47am UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430/2 "2025-11-18T11:47:09Z")

</div>

Interesting, IIRC it just works in PyCharm. I think the problem might be that there is a Python module named `Heartbeat_1_0.py`, which contains `class Heartbeat_1_0`, which is imported as `from Heartbeat_1_0 import Heartbeat_1_0` in the ` __init__.py`. The parser is apparently confusing the module with the class.

There are aliases without the minor version number, can you try these? In your case that would be `Heartbeat_1`. You could also try different import styles to see which one is accepted by the parser; e.g., `from uavcan.node import Heartbeat_1`.

The recommended practice is to actually omit the minor version number unless you care about it for some reason.

Also, `make_subscriber` can accept just the type without the fixed port-ID (it will fetch the ID automatically). You also shouldn’t explicitly access attributes prefixed with a `_`, they are private; the `nunavut_support` module provides public getters for them.

---

<div class="post-metadata">

**Author:** ![Scoeerg](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/scoeerg/32/1713_2.png) [@Scoeerg](https://forum.opencyphal.org/u/Scoeerg)\
**Post date:** [November 18, 2025, 1:58pm UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430/3 "2025-11-18T13:58:12Z")

</div>

Hi,

Yes `uavcan.node.Heartbeat_1._FIXED_PORT_ID_` works without the minor version number. Since it’s an alias, this will be stable even if the minor changes, and `Heartbeat_1` which currently is an alias to `Heartbeat_1_0` will then point to `Heartbeat_1_1`? I’ve only seen this once, but what if the major changes?

🙂 Thanks, then this is resolved.

---

<div class="post-metadata">

**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [November 18, 2025, 2:23pm UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430/4 "2025-11-18T14:23:14Z")

</div>

> [@Scoeerg](#):
>
> Since it’s an alias, this will be stable even if the minor changes, and `Heartbeat_1` which currently is an alias to `Heartbeat_1_0` will then point to `Heartbeat_1_1`?

Correct.

> [@Scoeerg](#):
>
> I’ve only seen this once, but what if the major changes?

Then you will need to update your code from `_1` to `_2`.

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<div class="post-metadata">

**Author:** ![Scoeerg](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/scoeerg/32/1713_2.png) [@Scoeerg](https://forum.opencyphal.org/u/Scoeerg)\
**Post date:** [November 18, 2025, 2:37pm UTC](https://forum.opencyphal.org/t/pycyphal-datatypes-with-intellisense-pylance/2430/5 "2025-11-18T14:37:57Z")

</div>

Fair enough. Breaking changes may break me, too.