Undefined name: import datetime for line 30

Without this change, line 30 will raise NameError at runtime.

lms/djangoapps/coursewarehistoryextended/migrations/0001_initial.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-
+import datetime
 
 from django.db import migrations, models
 import django.db.models.deletion