INCR-119 modernize openedx/core/djangoapps/certificates … (#20418)

* modernize openedx/core/djangoapps/certificates
openedx/core/djangoapps/commerce
openedx/core/djangoapps/common_initialization
openedx/core/djangoapps/config_model_utils

* rewmove unused import

openedx/core/djangoapps/certificates/api.py

 """
 The public API for certificates.
 """
+from __future__ import absolute_import
+
 import logging
 from datetime import datetime
 
+import six
 from pytz import UTC
 
 from lms.djangoapps.certificates.models import CertificateWhitelist
@@ -63,7 +66,7 @@ def can_show_certificate_message(course, student, course_grade, certificates_ena
     certificates_are_viewable = certificates_viewable_for_course(course)
 
     # Adding a temporary logging for EDUCATOR-2017.
-    if unicode(course.id) == u'course-v1:RITx+PM9004x+3T2017':
+    if six.text_type(course.id) == u'course-v1:RITx+PM9004x+3T2017':
         log.info(
             (
                 u'can_show_certificate_message called with:'

openedx/core/djangoapps/certificates/config/waffle.py

@@ -2,6 +2,8 @@
 This module contains various configuration settings via
 waffle switches for the Certificates app.
 """
+from __future__ import absolute_import
+
 from openedx.core.djangoapps.waffle_utils import WaffleSwitchNamespace
 
 # Namespace

openedx/core/djangoapps/certificates/tests/test_api.py

+from __future__ import absolute_import
+
+import itertools
 from contextlib import contextmanager
 from datetime import datetime, timedelta
-import itertools
 
 import ddt
 import pytz

openedx/core/djangoapps/commerce/utils.py

 """ Commerce API Service. """
+from __future__ import absolute_import
+
 from django.conf import settings
 from edx_rest_api_client.client import EdxRestApiClient
-
 from eventtracking import tracker
+
 from openedx.core.djangoapps.oauth_dispatch.jwt import create_jwt_for_user
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 
-
 ECOMMERCE_DATE_FORMAT = '%Y-%m-%dT%H:%M:%SZ'
 
 

openedx/core/djangoapps/common_initialization/apps.py

@@ -2,6 +2,8 @@
 Common initialization app for the LMS and CMS
 """
 
+from __future__ import absolute_import
+
 from django.apps import AppConfig
 
 

openedx/core/djangoapps/common_initialization/checks.py

@@ -5,6 +5,8 @@ Only populate this module with general settings validators which do not fit in
 other, more specific djangoapps.  Usually, settings which are widely used
 across the entire LMS or CMS can be validated here.
 """
+from __future__ import absolute_import
+
 from django.conf import settings
 from django.core.checks import Error, Tags, register
 

openedx/core/djangoapps/config_model_utils/admin.py

@@ -2,11 +2,11 @@
 Convenience classes for defining StackedConfigModel Admin pages.
 """
 
-from django import forms
-
-from opaque_keys.edx.keys import CourseKey
+from __future__ import absolute_import
 
 from config_models.admin import ConfigurationModelAdmin
+from django import forms
+from opaque_keys.edx.keys import CourseKey
 
 
 class CourseOverviewField(forms.ModelChoiceField):

openedx/core/djangoapps/config_model_utils/apps.py

@@ -2,7 +2,7 @@
 Django AppConfig for ConfigurationModel utilities
 """
 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from django.apps import AppConfig
 

openedx/core/djangoapps/config_model_utils/models.py

@@ -5,23 +5,23 @@ StackedConfigurationModel: A ConfigurationModel that can be overridden at site,
 """
 
 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import, unicode_literals
 
 from collections import defaultdict
 from enum import Enum
 
+import crum
+from config_models.models import ConfigurationModel, cache
 from django.conf import settings
-from django.db import models
-from django.db.models import Q, F
 from django.contrib.sites.models import Site
 from django.contrib.sites.requests import RequestSite
 from django.core.exceptions import ValidationError
+from django.db import models
+from django.db.models import Q
 from django.utils.translation import ugettext_lazy as _
-import crum
 
-from config_models.models import ConfigurationModel, cache
-from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
+from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
 from openedx.core.lib.cache_utils import request_cached
 
 

openedx/core/djangoapps/config_model_utils/utils.py

 """utils for feature-based enrollments"""
+from __future__ import absolute_import
+
 from experiments.models import ExperimentData
-from openedx.features.course_duration_limits.config import (
-    EXPERIMENT_ID,
-    EXPERIMENT_DATA_HOLDBACK_KEY
-)
+from openedx.features.course_duration_limits.config import EXPERIMENT_DATA_HOLDBACK_KEY, EXPERIMENT_ID
 
 
 def is_in_holdback(user):