diff --git a/problem/tests.py b/problem/tests.py
index 0aeefb0c..caa6ad68 100644
--- a/problem/tests.py
+++ b/problem/tests.py
@@ -17,7 +17,7 @@ class ProblemTagListAPITest(APITestCase):
         ProblemTag.objects.create(name="name2")
         resp = self.client.get(self.reverse("problem_tag_list_api"))
         self.assertSuccess(resp)
-        resp_data = resp.data['data']
+        resp_data = resp.data["data"]
         self.assertEqual(resp_data[0]["name"], "name1")
         self.assertEqual(resp_data[1]["name"], "name2")
 
diff --git a/problem/views/oj.py b/problem/views/oj.py
index ffce4051..611c2c96 100644
--- a/problem/views/oj.py
+++ b/problem/views/oj.py
@@ -37,7 +37,7 @@ class ProblemAPI(APIView):
             problems = problems.filter(Q(title__contains=keyword) | Q(description__contains=keyword))
 
         # 难度筛选
-        difficulty_rank = request.GET.get('difficulty', None)
+        difficulty_rank = request.GET.get("difficulty", None)
         if difficulty_rank:
             problems = problems.filter(difficulty=difficulty_rank)