diff --git a/arkindex_worker/worker/version.py b/arkindex_worker/worker/version.py
index f32fdc3a2f3dc1780113bcf3d451e15841a88aee..39d75aabe2bd22624cdcf161fa82c9155b309e50 100644
--- a/arkindex_worker/worker/version.py
+++ b/arkindex_worker/worker/version.py
@@ -14,7 +14,6 @@ class WorkerVersionMixin(object):
 
         return worker_version
 
-
     def get_ml_result_slug(self, ml_result) -> str:
         """
         Helper function to get the worker slug from element, classification or transcription.
@@ -24,13 +23,13 @@ class WorkerVersionMixin(object):
         """
 
         # Handle cached models
-        if hasattr(ml_result, 'worker_version_id'):
+        if hasattr(ml_result, "worker_version_id"):
             worker_version_id = ml_result.worker_version_id
         elif "worker_version" in ml_result:
-            worker_version_id = ml_result['worker_version']
+            worker_version_id = ml_result["worker_version"]
         # transcriptions have worker_version_id but elements have worker_version
         elif "worker_version_id" in ml_result:
-            worker_version_id = ml_result['worker_version_id']
+            worker_version_id = ml_result["worker_version_id"]
         else:
             raise ValueError(f"Unable to get slug from: {ml_result}")
 
@@ -38,4 +37,4 @@ class WorkerVersionMixin(object):
             return
 
         worker_version = self.get_worker_version(worker_version_id)
-        return worker_version['worker']['slug']
+        return worker_version["worker"]["slug"]
diff --git a/tests/test_elements_worker/test_worker.py b/tests/test_elements_worker/test_worker.py
index 6c520a9dc8704ab614ec0d280d3a8495abe8d069..ce85d12dd14b8cff0ec4a40d434c87c221a79e3d 100644
--- a/tests/test_elements_worker/test_worker.py
+++ b/tests/test_elements_worker/test_worker.py
@@ -4,8 +4,8 @@ import json
 import pytest
 from apistar.exceptions import ErrorResponse
 
-from arkindex_worker.models import Element
 from arkindex_worker.cache import CachedElement
+from arkindex_worker.models import Element
 from arkindex_worker.worker import ActivityState
 
 # Common API calls for all workers
@@ -123,9 +123,7 @@ def test_get_ml_result_slug__ok(mocker, fake_dummy_worker, ml_result, expected_s
     fake_dummy_worker.get_worker_version = mocker.MagicMock()
     fake_dummy_worker.get_worker_version.return_value = {
         "id": TEST_VERSION_ID,
-        "worker": {
-            "slug": "mock_slug"
-        }
+        "worker": {"slug": "mock_slug"},
     }
 
     slug = fake_dummy_worker.get_ml_result_slug(ml_result)