diff --git a/duty_teller/api/app.py b/duty_teller/api/app.py
index 87bc7bb..35407e7 100644
--- a/duty_teller/api/app.py
+++ b/duty_teller/api/app.py
@@ -374,9 +374,7 @@ def admin_reassign_duty(
             status_code=400,
             detail=t(lang, "admin.user_not_found"),
         )
-    updated = update_duty_user(
-        session, duty_id, body.user_id, commit=True
-    )
+    updated = update_duty_user(session, duty_id, body.user_id, commit=True)
     if updated is None:
         raise HTTPException(
             status_code=404,
diff --git a/tests/test_admin_api.py b/tests/test_admin_api.py
index 20803f7..7a78f72 100644
--- a/tests/test_admin_api.py
+++ b/tests/test_admin_api.py
@@ -39,7 +39,12 @@ def test_admin_me_returns_is_admin_true_when_admin(
     mock_get_user.return_value = SimpleNamespace(full_name="Admin", username="admin")
     mock_can_access.return_value = True
     mock_is_admin.return_value = True
-    r = client.get("/api/admin/me", headers={"X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A100%7D&hash=x"})
+    r = client.get(
+        "/api/admin/me",
+        headers={
+            "X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A100%7D&hash=x"
+        },
+    )
     assert r.status_code == 200
     assert r.json() == {"is_admin": True}
 
@@ -59,7 +64,12 @@ def test_admin_me_returns_is_admin_false_when_not_admin(
     mock_get_user.return_value = SimpleNamespace(full_name="User", username="user")
     mock_can_access.return_value = True
     mock_is_admin.return_value = False
-    r = client.get("/api/admin/me", headers={"X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A200%7D&hash=x"})
+    r = client.get(
+        "/api/admin/me",
+        headers={
+            "X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A200%7D&hash=x"
+        },
+    )
     assert r.status_code == 200
     assert r.json() == {"is_admin": False}
 
@@ -91,7 +101,9 @@ def test_admin_users_403_when_not_admin(
     mock_is_admin.return_value = False  # not admin
     r = client.get(
         "/api/admin/users",
-        headers={"X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A100%7D&hash=x"},
+        headers={
+            "X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A100%7D&hash=x"
+        },
     )
     assert r.status_code == 403
     detail = r.json()["detail"]
@@ -239,7 +251,9 @@ def test_admin_reassign_400_when_user_not_found(
         r = client.patch(
             "/api/admin/duties/1",
             json={"user_id": 999},
-            headers={"X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A1%7D&hash=x"},
+            headers={
+                "X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A1%7D&hash=x"
+            },
         )
     assert r.status_code == 400
     mock_update.assert_not_called()
@@ -293,7 +307,9 @@ def test_admin_reassign_200_updates_and_invalidates(
         r = client.patch(
             "/api/admin/duties/1",
             json={"user_id": 2},
-            headers={"X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A1%7D&hash=x"},
+            headers={
+                "X-Telegram-Init-Data": "auth_date=1&user=%7B%22id%22%3A1%7D&hash=x"
+            },
         )
     assert r.status_code == 200
     data = r.json()