Remove unused imports

lms/djangoapps/instructor_task/tasks_helper.py

@@ -18,7 +18,7 @@ from celery import Task, current_task
 from celery.states import SUCCESS, FAILURE
 from django.contrib.auth.models import User
 from django.core.files.storage import DefaultStorage
-from django.db import transaction, reset_queries
+from django.db import reset_queries
 from django.db.models import Q
 import dogstats_wrapper as dog_stats_api
 from pytz import UTC