Fix cpu count detection (#527)

* Update __init__.py

* Update CHANGELOG.md

Author: grst

CHANGELOG.md

@@ -8,6 +8,12 @@ and this project adheres to [Semantic Versioning][].
 [keep a changelog]: https://keepachangelog.com/en/1.0.0/
 [semantic versioning]: https://semver.org/spec/v2.0.0.html
 
+## v0.17.2
+
+### Fixes
+
+-   Detection of CPU count in `define_clonotype_clusters` was broken ([#527](https://github.com/scverse/scirpy/pull/527))
+
 ## v0.17.1
 
 ### Fixes

src/scirpy/util/__init__.py

@@ -598,6 +598,6 @@ def _get_usable_cpus(n_jobs: int = 0):
         return n_jobs
 
     try:
-        return os.sched_getaffinity(0)
+        return len(os.sched_getaffinity(0))
     except AttributeError:
         return os.cpu_count()