INCR-166 Run python-modernize on openedx/core/djangolib (#20473)

* INCR-166 Run python-modernize on openedx/core/djangolib

* INCR-166 disabled harmless errors and added docstring

openedx/core/djangolib/fields.py

@@ -1,6 +1,7 @@
 """
 Custom Django fields.
 """
+from __future__ import absolute_import
 from django.db import models
 
 

openedx/core/djangolib/js_utils.py

@@ -1,6 +1,7 @@
 """
 Utilities for dealing with Javascript and JSON.
 """
+from __future__ import absolute_import
 import json
 
 from django.utils.html import escapejs

openedx/core/djangolib/markup.py

@@ -2,6 +2,7 @@
 Utilities for use in Mako markup.
 """
 
+from __future__ import absolute_import
 import markupsafe
 import bleach
 from mako.filters import decode

openedx/core/djangolib/oauth2_retirement_utils.py

@@ -2,6 +2,7 @@
 Removes user PII from OAuth2 models.
 """
 
+from __future__ import absolute_import
 from oauth2_provider.models import (
     AccessToken as DOTAccessToken,
     Application as DOTApplication,

openedx/core/djangolib/testing/tests/test_utils.py

@@ -1,6 +1,7 @@
 """
 Test that testing utils do what they say.
 """
+from __future__ import absolute_import
 from crum import set_current_request
 
 from django.contrib.auth import get_user_model

openedx/core/djangolib/testing/utils.py

@@ -8,6 +8,7 @@ Utility classes for testing django applications.
     A TestCase baseclass that has per-test isolated caches.
 """
 
+from __future__ import absolute_import
 import copy
 import re
 from unittest import skipUnless

openedx/core/djangolib/tests/test_js_utils.py

@@ -3,13 +3,15 @@
 """
 Tests for js_utils.py
 """
-import HTMLParser
+from __future__ import absolute_import
+import six.moves.html_parser  # pylint: disable=import-error
 import json
 from unittest import TestCase
 
 from mako.template import Template
 
 from openedx.core.djangolib.js_utils import dump_js_escaped_json, js_escaped_string
+import six  # pylint: disable=ungrouped-imports
 
 
 class TestJSUtils(TestCase):
@@ -71,7 +73,7 @@ class TestJSUtils(TestCase):
         """
         malicious_js_string = "</script><script>alert('hello, ');</script>"
 
-        expected_escaped_string_for_js = unicode(
+        expected_escaped_string_for_js = six.text_type(
             r"\u003C/script\u003E\u003Cscript\u003Ealert(\u0027hello, \u0027)\u003B\u003C/script\u003E"
         )
         escaped_string_for_js = js_escaped_string(malicious_js_string)
@@ -179,7 +181,7 @@ class TestJSUtils(TestCase):
                 should be parseable into a near equivalent to test_dict.
 
         """
-        html_parser = HTMLParser.HTMLParser()
+        html_parser = six.moves.html_parser.HTMLParser()
 
         expected_json = html_parser.unescape(expected_json_for_html_string)
         parsed_expected_dict = json.loads(expected_json)

openedx/core/djangolib/tests/test_markup.py

@@ -3,6 +3,7 @@
 Tests for openedx.core.djangolib.markup
 """
 
+from __future__ import absolute_import
 import unittest
 
 import ddt
@@ -11,6 +12,7 @@ from django.utils.translation import ungettext
 from mako.template import Template
 
 from openedx.core.djangolib.markup import HTML, Text, strip_all_tags_but_br
+import six
 
 
 @ddt.ddt
@@ -27,8 +29,8 @@ class FormatHtmlTest(unittest.TestCase):
     )
     def test_simple(self, before_after):
         (before, after) = before_after
-        self.assertEqual(unicode(Text(_(before))), after)
-        self.assertEqual(unicode(Text(before)), after)
+        self.assertEqual(six.text_type(Text(_(before))), after)  # pylint: disable=translation-of-non-string
+        self.assertEqual(six.text_type(Text(before)), after)
 
     def test_formatting(self):
         # The whole point of this function is to make sure this works:
@@ -37,7 +39,7 @@ class FormatHtmlTest(unittest.TestCase):
             end=HTML("</a>"),
         )
         self.assertEqual(
-            unicode(out),
+            six.text_type(out),
             u"Point &amp; click <a href='http://edx.org'>here</a>!",
         )
 
@@ -49,7 +51,7 @@ class FormatHtmlTest(unittest.TestCase):
             end=HTML("</a>"),
         )
         self.assertEqual(
-            unicode(out),
+            six.text_type(out),
             u"Send <a href='mailto:A&amp;B'>email</a>",
         )
 

openedx/core/djangolib/tests/test_oauth2_retirement_utils.py

@@ -2,6 +2,7 @@
 Contains tests for OAuth2 model-retirement methods.
 """
 
+from __future__ import absolute_import
 import datetime
 
 from django.test import TestCase

openedx/core/djangolib/tests/test_translation_utils.py

@@ -3,6 +3,7 @@
 Tests for openedx.core.djangolib.translation_utils
 """
 
+from __future__ import absolute_import
 import unittest
 
 import datetime

openedx/core/djangolib/translation_utils.py

@@ -1,3 +1,8 @@
+"""
+i18n utility functions
+"""
+
+from __future__ import absolute_import
 from django.utils.translation import ugettext as _, override
 from django.utils.formats import dateformat, get_format