diff --git a/apps/course/models.py b/apps/course/models.py
index dee55975..14d77132 100644
--- a/apps/course/models.py
+++ b/apps/course/models.py
@@ -1,6 +1,7 @@
 import arrow
 from uuid import uuid4
 from django.db import models
+from django.core.exceptions import ValidationError
 from django.utils import timezone
 from django.utils.text import slugify
 from django.utils.timezone import now