Remove unused imports

app/dao/monthly_billing_dao.py

@@ -1,7 +1,5 @@
 from datetime import datetime
 
-from sqlalchemy import func
-
 
 from app import db
 from app.dao.dao_utils import transactional

tests/app/dao/test_monthly_billing.py

@@ -3,7 +3,6 @@ from dateutil.relativedelta import relativedelta
 from freezegun import freeze_time
 from functools import partial
 
-from app import db
 from app.dao.monthly_billing_dao import (
     create_or_update_monthly_billing,
     get_monthly_billing_entry,