diff --git a/judge/models/__init__.py b/judge/models/__init__.py
index 3ace951a1..b01768483 100644
--- a/judge/models/__init__.py
+++ b/judge/models/__init__.py
@@ -5,8 +5,8 @@
 from judge.models.contest import Contest, ContestAnnouncement, ContestMoss, ContestParticipation, ContestProblem, \
     ContestSubmission, ContestTag, Rating
 from judge.models.interface import BlogPost, BlogVote, MiscConfig, NavigationBar, validate_regex
-from judge.models.problem import LanguageLimit, License, Problem, ProblemClarification, ProblemGroup, \
-    ProblemExportKey, ProblemTranslation, ProblemType, Solution, SubmissionSourceAccess, TranslatedProblemQuerySet
+from judge.models.problem import LanguageLimit, License, Problem, ProblemClarification, ProblemExportKey, \
+    ProblemGroup, ProblemTranslation, ProblemType, Solution, SubmissionSourceAccess, TranslatedProblemQuerySet
 from judge.models.problem_data import CHECKERS, ProblemData, ProblemTestCase, problem_data_storage, \
     problem_directory_file
 from judge.models.profile import Badge, Organization, OrganizationMonthlyUsage, OrganizationRequest, \
diff --git a/judge/template_context.py b/judge/template_context.py
index 24b549aee..42c4383cd 100644
--- a/judge/template_context.py
+++ b/judge/template_context.py
@@ -109,4 +109,4 @@ def math_setting(request):
 
 
 def site_setting(request):
-    return {'VNOJ_PROBLEM_ENABLE_IMPORT': settings.VNOJ_PROBLEM_ENABLE_IMPORT}
\ No newline at end of file
+    return {'VNOJ_PROBLEM_ENABLE_IMPORT': settings.VNOJ_PROBLEM_ENABLE_IMPORT}
diff --git a/judge/views/problem_transfer.py b/judge/views/problem_transfer.py
index f8e8cbbea..2b7b0decb 100644
--- a/judge/views/problem_transfer.py
+++ b/judge/views/problem_transfer.py
@@ -1,15 +1,15 @@
 import base64
 import hmac
-import requests
 import struct
 
+import requests
 from django.conf import settings
 from django.contrib.auth.models import AnonymousUser
 from django.core.exceptions import PermissionDenied, ValidationError
 from django.core.validators import RegexValidator
 from django.db.models import Q
-from django.forms import Form, CharField, PasswordInput, URLField
-from django.http import Http404, JsonResponse, HttpResponseRedirect
+from django.forms import CharField, Form
+from django.http import Http404, HttpResponseRedirect, JsonResponse
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.decorators import method_decorator
@@ -22,7 +22,7 @@
 from requests.exceptions import HTTPError
 from reversion import revisions
 
-from judge.models import Problem, ProblemExportKey, ProblemGroup, ProblemType, Language
+from judge.models import Language, Problem, ProblemExportKey, ProblemGroup, ProblemType
 from judge.utils.views import TitleMixin
 from judge.widgets import HeavySelect2Widget