Fix linting

apps/note/models/notes.py

@@ -5,7 +5,7 @@ import unicodedata
 
 from django.conf import settings
 from django.conf.global_settings import DEFAULT_FROM_EMAIL
-from django.core.exceptions import ValidationError, PermissionDenied
+from django.core.exceptions import ValidationError
 from django.core.mail import send_mail
 from django.core.validators import RegexValidator
 from django.db import models, transaction

apps/note/models/transactions.py

@@ -3,7 +3,6 @@
 
 from django.core.exceptions import ValidationError
 from django.db import models, transaction
-from django.db.models import F
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _