diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7c3e7e799..d337a46d8 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.8.6
+    rev: v0.9.1
     hooks:
       - id: ruff
         args: [ --fix ]
diff --git a/oauth2_provider/models.py b/oauth2_provider/models.py
index 0467ddfa1..a76db37c0 100644
--- a/oauth2_provider/models.py
+++ b/oauth2_provider/models.py
@@ -715,7 +715,7 @@ def batch_delete(queryset, query):
             flat_queryset = queryset.values_list("id", flat=True)[:CLEAR_EXPIRED_TOKENS_BATCH_SIZE]
             batch_length = flat_queryset.count()
             queryset.model.objects.filter(id__in=list(flat_queryset)).delete()
-            logger.debug(f"{batch_length} tokens deleted, {current_no-batch_length} left")
+            logger.debug(f"{batch_length} tokens deleted, {current_no - batch_length} left")
             queryset = queryset.model.objects.filter(query)
             time.sleep(CLEAR_EXPIRED_TOKENS_BATCH_INTERVAL)
             current_no = queryset.count()
diff --git a/tests/test_models.py b/tests/test_models.py
index 32ca07627..2c7ff8114 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -433,25 +433,25 @@ def test_clear_expired_tokens_with_tokens(self):
         initial_at_count = AccessToken.objects.count()
         assert initial_at_count == 2 * self.num_tokens, f"{2 * self.num_tokens} access tokens should exist."
         initial_expired_at_count = AccessToken.objects.filter(expires__lte=self.now).count()
-        assert (
-            initial_expired_at_count == self.num_tokens
-        ), f"{self.num_tokens} expired access tokens should exist."
+        assert initial_expired_at_count == self.num_tokens, (
+            f"{self.num_tokens} expired access tokens should exist."
+        )
         initial_current_at_count = AccessToken.objects.filter(expires__gt=self.now).count()
-        assert (
-            initial_current_at_count == self.num_tokens
-        ), f"{self.num_tokens} current access tokens should exist."
+        assert initial_current_at_count == self.num_tokens, (
+            f"{self.num_tokens} current access tokens should exist."
+        )
         initial_rt_count = RefreshToken.objects.count()
-        assert (
-            initial_rt_count == self.num_tokens // 2
-        ), f"{self.num_tokens // 2} refresh tokens should exist."
+        assert initial_rt_count == self.num_tokens // 2, (
+            f"{self.num_tokens // 2} refresh tokens should exist."
+        )
         initial_rt_expired_at_count = RefreshToken.objects.filter(access_token__expires__lte=self.now).count()
-        assert (
-            initial_rt_expired_at_count == initial_rt_count / 2
-        ), "half the refresh tokens should be for expired access tokens."
+        assert initial_rt_expired_at_count == initial_rt_count / 2, (
+            "half the refresh tokens should be for expired access tokens."
+        )
         initial_rt_current_at_count = RefreshToken.objects.filter(access_token__expires__gt=self.now).count()
-        assert (
-            initial_rt_current_at_count == initial_rt_count / 2
-        ), "half the refresh tokens should be for current access tokens."
+        assert initial_rt_current_at_count == initial_rt_count / 2, (
+            "half the refresh tokens should be for current access tokens."
+        )
         initial_gt_count = Grant.objects.count()
         assert initial_gt_count == self.num_tokens * 2, f"{self.num_tokens * 2} grants should exist."
 
@@ -459,15 +459,15 @@ def test_clear_expired_tokens_with_tokens(self):
 
         # after clear_expired():
         remaining_at_count = AccessToken.objects.count()
-        assert (
-            remaining_at_count == initial_at_count // 2
-        ), "half the initial access tokens should still exist."
+        assert remaining_at_count == initial_at_count // 2, (
+            "half the initial access tokens should still exist."
+        )
         remaining_expired_at_count = AccessToken.objects.filter(expires__lte=self.now).count()
         assert remaining_expired_at_count == 0, "no remaining expired access tokens should still exist."
         remaining_current_at_count = AccessToken.objects.filter(expires__gt=self.now).count()
-        assert (
-            remaining_current_at_count == initial_current_at_count
-        ), "all current access tokens should still exist."
+        assert remaining_current_at_count == initial_current_at_count, (
+            "all current access tokens should still exist."
+        )
         remaining_rt_count = RefreshToken.objects.count()
         assert remaining_rt_count == initial_rt_count // 2, "half the refresh tokens should still exist."
         remaining_rt_expired_at_count = RefreshToken.objects.filter(
@@ -477,9 +477,9 @@ def test_clear_expired_tokens_with_tokens(self):
         remaining_rt_current_at_count = RefreshToken.objects.filter(
             access_token__expires__gt=self.now
         ).count()
-        assert (
-            remaining_rt_current_at_count == initial_rt_current_at_count
-        ), "all the refresh tokens for current access tokens should still exist."
+        assert remaining_rt_current_at_count == initial_rt_current_at_count, (
+            "all the refresh tokens for current access tokens should still exist."
+        )
         remaining_gt_count = Grant.objects.count()
         assert remaining_gt_count == initial_gt_count // 2, "half the remaining grants should still exist."