_See all documentation for this version [here](https://qrules.rtfd.io/en/0.9.7)._
🐛 Bug fixes
<details>
<summary>ReactionInfo is now hashable (151)</summary>
This is particularly useful for [`functools.lru_cache()`](https://docs.python.org/3/library/functools.html#functools.lru_cache).
</details>
🔨 Internal maintenance
<details>
<summary>Switched to the new attrs API (152)</summary>
See [`import attrs`](https://hynek.me/articles/import-attrs/#the-last-step-import-attrs) and [`attrs` TNG](https://www.attrs.org/en/21.4.0/names.html#attrs-tng).
</details>
<details>
<summary>implement_pretty_repr() decorator is now implement_pretty_repr (154)</summary>
The `implement_pretty_repr()` decorator does not take any arguments, so one level can be removed. This changes it's usage from:
python
implement_pretty_repr() old
attrs.define
class SomeClass:
...
to
python
implement_pretty_repr <-- new
attrs.define
class SomeClass:
...
</details>
📝 Documentation
<details>
<summary>Type hints are abbreviated where possible (154)</summary>
Type hints are abbreviated with [`autodoc_typehints_format`](https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html#confval-autodoc_typehints_format). But note that this does not yet work perfectly because of QRules' [custom reference relinking](https://github.com/ComPWA/qrules/commit/837923872c85e43b765ee7c5a3d6e415d8e330ad).
</details>
<details>
<summary>API is now sorted by position in the source code (154)</summary>
API is now sorted by position in the source code, **not alphabetically**.
</details>
<details>
<summary>Left sidebar is unfolded unto the second level (148)</summary>
Also unfolds the left sidebar unto the second level, like in https://github.com/ComPWA/ampform/pull/221 and https://github.com/ComPWA/tensorwaves/pull/407. Preview [here](https://qrules--148.org.readthedocs.build/en/148).
</details>
<details>
<summary>Added Hypothesis and utterances overlay to allow commenting on the documentation (149)</summary>
Closes https://github.com/ComPWA/compwa-org/issues/109
</details>
<details>
<summary>Explained how to pin dependencies with Conda (150)</summary>
Preview [here](https://qrules--150.org.readthedocs.build/en/150/install.html). See also https://github.com/ComPWA/tensorwaves/pull/411.
</details>
🖱️ Developer Experience
<details>
<summary>Upgrade cron job are now on even weeks only (148 and 153)</summary>
See https://github.com/ComPWA/repo-maintenance/pull/48
</details>