chore: fix some lint and isort errors

Author: iloveagent57

enterprise_access/apps/api/v1/views/customer_billing.py

@@ -530,6 +530,10 @@ def list(self, request, *args, **kwargs):
         url_path='first-invoice-upcoming-amount-due',
     )
     def first_upcoming_invoice_amount_due(self, request, *args, **kwargs):
+        """
+        Given a license-manager SubscriptionPlan uuid, returns an upcoming
+        invoice amount due, dervied from Stripe's preview invoice API.
+        """
         subscription_plan_uuid = self.request.query_params.get('subscription_plan_uuid')
         summary = StripeEventSummary.objects.filter(
             event_type='customer.subscription.created',

enterprise_access/apps/customer_billing/tests/test_models.py

@@ -4,7 +4,7 @@
 from datetime import timedelta
 from decimal import Decimal
 from random import randint
-from typing import Type, cast
+from typing import cast
 from unittest import mock
 from uuid import uuid4
 

enterprise_access/apps/provisioning/models.py

@@ -3,11 +3,11 @@
 """
 import logging
 from datetime import datetime
-from dateutil.relativedelta import relativedelta
 from typing import Optional
 from uuid import UUID
 
 from attrs import define, field, validators
+from dateutil.relativedelta import relativedelta
 from django.conf import settings
 from django_countries import countries
 

enterprise_access/apps/subsidy_request/tests/factories.py

@@ -8,7 +8,6 @@
 import factory
 from faker import Faker
 
-from enterprise_access.apps.content_assignments.tests.factories import LearnerContentAssignmentFactory
 from enterprise_access.apps.core.tests.factories import UserFactory
 from enterprise_access.apps.subsidy_request.constants import SubsidyRequestStates, SubsidyTypeChoices
 from enterprise_access.apps.subsidy_request.models import (