diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index d1ebd1d..9420974 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -71,4 +71,3 @@ This Code of Conduct is adapted from the [Contributor Covenant][homepage], versi
 available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
 
 [homepage]: https://www.contributor-covenant.org
-
diff --git a/LICENSE b/LICENSE
index b49930c..c8b4a8a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -4,10 +4,10 @@ All rights reserved.
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:
 
-    1. Redistributions of source code must retain the above copyright notice, 
+    1. Redistributions of source code must retain the above copyright notice,
        this list of conditions and the following disclaimer.
-    
-    2. Redistributions in binary form must reproduce the above copyright 
+
+    2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
 
diff --git a/README.rst b/README.rst
index f0697dc..ec1f3da 100644
--- a/README.rst
+++ b/README.rst
@@ -14,7 +14,7 @@ django-import-export
     :alt: Current version on PyPi
 
 .. image:: http://readthedocs.org/projects/django-import-export/badge/?version=stable
-    :target: http://django-import-export.readthedocs.io/en/stable/
+    :target: https://django-import-export.readthedocs.io/en/stable/
     :alt: Documentation
 
 django-import-export is a Django application and library for importing
@@ -36,7 +36,7 @@ Features:
 .. image:: docs/_static/images/django-import-export-change.png
 
 
-* Documentation: http://django-import-export.readthedocs.io/en/stable/
+* Documentation: https://django-import-export.readthedocs.io/en/stable/
 * GitHub: https://github.com/django-import-export/django-import-export/
 * Free software: BSD license
 * PyPI: https://pypi.org/project/django-import-export/
diff --git a/docs/api_widgets.rst b/docs/api_widgets.rst
index f956ca3..94b69a5 100644
--- a/docs/api_widgets.rst
+++ b/docs/api_widgets.rst
@@ -28,7 +28,7 @@ Widgets
 
 .. autoclass:: import_export.widgets.DurationWidget
    :members:
-   
+
 .. autoclass:: import_export.widgets.JSONWidget
    :members:
 
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 7b7568f..012e83c 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -17,7 +17,7 @@ Changelog
 
 - JSONWidget for jsonb fields (#803)
 
-- Add ExportActionMixin (#809) 
+- Add ExportActionMixin (#809)
 
 - Add Import Export Permissioning #608 (#804)
 
@@ -166,7 +166,7 @@ Changelog
 
 - Append rows to Result object via function call to allow overriding (#462)
 
-- Add get_resource_kwargs to allow passing request to resource (#457) 
+- Add get_resource_kwargs to allow passing request to resource (#457)
 
 - Expose Django user to get_export_data() and export() (#447)
 
diff --git a/import_export/admin.py b/import_export/admin.py
index 7f8409a..a3bfbc2 100644
--- a/import_export/admin.py
+++ b/import_export/admin.py
@@ -20,7 +20,6 @@ try:
 except ImportError:  # Django<2.0
     from django.core.urlresolvers import reverse
 from django.conf import settings
-from django.template.defaultfilters import pluralize
 from django.utils.decorators import method_decorator
 from django.utils.encoding import force_text
 from django.views.decorators.http import require_POST
diff --git a/import_export/formats/base_formats.py b/import_export/formats/base_formats.py
index 7933760..57b5cb2 100644
--- a/import_export/formats/base_formats.py
+++ b/import_export/formats/base_formats.py
@@ -77,7 +77,7 @@ class Format(object):
 
     def get_content_type(self):
         # For content types see
-        # http://www.iana.org/assignments/media-types/media-types.xhtml
+        # https://www.iana.org/assignments/media-types/media-types.xhtml
         return 'application/octet-stream'
 
     def can_import(self):
@@ -156,7 +156,7 @@ class JSON(TextFormat):
 
 class YAML(TextFormat):
     TABLIB_MODULE = 'tablib.formats._yaml'
-    # See http://stackoverflow.com/questions/332129/yaml-mime-type
+    # See https://stackoverflow.com/questions/332129/yaml-mime-type
     CONTENT_TYPE = 'text/yaml'
 
 
diff --git a/import_export/mixins.py b/import_export/mixins.py
index 5e44c19..abf3a32 100644
--- a/import_export/mixins.py
+++ b/import_export/mixins.py
@@ -64,7 +64,7 @@ class ExportViewMixin(object):
 
 
 class ExportViewFormMixin(ExportViewMixin, FormView):
-    def form_valid(self, form): 
+    def form_valid(self, form):
         formats = self.get_export_formats()
         file_format = formats[
             int(form.cleaned_data['file_format'])
diff --git a/import_export/resources.py b/import_export/resources.py
index 3d04b9c..152222b 100644
--- a/import_export/resources.py
+++ b/import_export/resources.py
@@ -9,7 +9,6 @@ from copy import deepcopy
 
 from diff_match_patch import diff_match_patch
 
-from django import VERSION
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.core.management.color import no_style
diff --git a/import_export/widgets.py b/import_export/widgets.py
index 67b1fe1..6f4ccda 100644
--- a/import_export/widgets.py
+++ b/import_export/widgets.py
@@ -264,7 +264,7 @@ class SimpleArrayWidget(Widget):
     def render(self, value, obj=None):
         return self.separator.join(six.text_type(v) for v in value)
 
-    
+
 class JSONWidget(Widget):
     """
     Widget for a JSON object (especially required for jsonb fields in PostgreSQL database.)
@@ -305,7 +305,7 @@ class ForeignKeyWidget(Widget):
 
         from import_export import fields, resources
         from import_export.widgets import ForeignKeyWidget
-        
+
         class BookResource(resources.ModelResource):
             author = fields.Field(
                 column_name='author',
diff --git a/setup.py b/setup.py
index 23864d3..fc85b82 100644
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,4 @@
-from distutils.core import setup
-from setuptools import find_packages
+from setuptools import find_packages, setup
 
 
 VERSION = __import__("import_export").__version__
diff --git a/tests/core/tests/test_admin_integration.py b/tests/core/tests/test_admin_integration.py
index 403e1b9..f34a4cb 100644
--- a/tests/core/tests/test_admin_integration.py
+++ b/tests/core/tests/test_admin_integration.py
@@ -64,7 +64,7 @@ class ImportExportAdminIntegrationTest(TestCase):
         response = self.client.post('/admin/core/book/process_import/', data,
                                     follow=True)
         self.assertEqual(response.status_code, 200)
-        self.assertContains(response, 
+        self.assertContains(response,
             _('Import finished, with {} new and {} updated {}.').format(
                 1, 0, Book._meta.verbose_name_plural)
         )
@@ -101,7 +101,7 @@ class ImportExportAdminIntegrationTest(TestCase):
         response = self.client.post('/admin/core/book/process_import/', data,
                                     follow=True)
         self.assertEqual(response.status_code, 200)
-        self.assertContains(response, 
+        self.assertContains(response,
             _('Import finished, with {} new and {} updated {}.').format(
                 1, 0, Book._meta.verbose_name_plural)
         )
@@ -207,7 +207,7 @@ class ImportExportAdminIntegrationTest(TestCase):
         self.assertEqual(child.object_id, str(1))
 
     def test_logentry_creation_with_import_obj_exception(self):
-        # from http://mail.python.org/pipermail/python-dev/2008-January/076194.html
+        # from https://mail.python.org/pipermail/python-dev/2008-January/076194.html
         def monkeypatch_method(cls):
             def decorator(func):
                 setattr(cls, func.__name__, func)
diff --git a/tests/core/tests/test_permissions.py b/tests/core/tests/test_permissions.py
index f366c71..ce30bb5 100644
--- a/tests/core/tests/test_permissions.py
+++ b/tests/core/tests/test_permissions.py
@@ -2,18 +2,10 @@ from __future__ import unicode_literals
 
 import os.path
 
-from django.contrib.auth import get_permission_codename
 from django.contrib.auth.models import Permission
 from django.test.utils import override_settings
 from django.test.testcases import TestCase
 from django.contrib.auth.models import User
-from django.core.files.uploadedfile import SimpleUploadedFile
-from django.utils.translation import ugettext_lazy as _
-from django.contrib.admin.models import LogEntry
-from tablib import Dataset
-
-from core.admin import BookAdmin, AuthorAdmin, BookResource
-from core.models import Category, Parent, Book
 
 
 class ImportExportPermissionTest(TestCase):
diff --git a/tests/core/tests/test_resources.py b/tests/core/tests/test_resources.py
index 85838d9..9b0e342 100644
--- a/tests/core/tests/test_resources.py
+++ b/tests/core/tests/test_resources.py
@@ -1,12 +1,12 @@
 from __future__ import unicode_literals
 
 import tablib
+from collections import OrderedDict
 from copy import deepcopy
 from datetime import date
 from decimal import Decimal
 from unittest import skip, skipUnless
 
-from django import VERSION
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.db import IntegrityError, DatabaseError
@@ -25,11 +25,6 @@ from ..models import (
     WithFloatField, Person, Role
 )
 
-try:
-    from collections import OrderedDict
-except ImportError:
-    from django.utils.datastructures import SortedDict as OrderedDict
-
 
 class MyResource(resources.Resource):
     name = fields.Field()
diff --git a/tests/core/tests/test_widgets.py b/tests/core/tests/test_widgets.py
index 7671692..39af41e 100644
--- a/tests/core/tests/test_widgets.py
+++ b/tests/core/tests/test_widgets.py
@@ -3,7 +3,6 @@ from __future__ import unicode_literals
 
 from decimal import Decimal
 from datetime import date, datetime, time, timedelta
-from unittest import SkipTest
 
 from django.test.utils import override_settings
 from django.test import TestCase
diff --git a/tests/database.db b/tests/database.db
index 73a7485..a252d0b 100644
Binary files a/tests/database.db and b/tests/database.db differ
diff --git a/tests/urls.py b/tests/urls.py
index 9a7f076..57c8709 100644
--- a/tests/urls.py
+++ b/tests/urls.py
@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 
-from django.conf.urls import url, include
+from django.conf.urls import url
 from django.contrib.staticfiles.urls import staticfiles_urlpatterns
 
 from django.contrib import admin