Support for python3 is needed

[ManPython]

@saxix Do you planing update the django-site-maintenance?

 File "E:\Python36\lib\site-packages\django\core\servers\basehttp.py", line 45, in get_internal_wsgi_appl
ication
    return import_string(app_path)
  File "E:\Python36\lib\site-packages\django\utils\module_loading.py", line 17, in import_string
    module = import_module(module_path)
  File "E:\Python36\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "E:\django\_app\wsgi.py", line 17, in <module>
    application = get_wsgi_application()
  File "E:\Python36\lib\site-packages\django\core\wsgi.py", line 13, in get_wsgi_application
    return WSGIHandler()
  File "E:\Python36\lib\site-packages\django\core\handlers\wsgi.py", line 135, in __init__
    self.load_middleware()
  File "E:\Python36\lib\site-packages\django\core\handlers\base.py", line 35, in load_middleware
    middleware = import_string(middleware_path)
  File "E:\Python36\lib\site-packages\django\utils\module_loading.py", line 17, in import_string
    module = import_module(module_path)
  File "E:\Python36\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "E:\Python36\lib\site-packages\maintenance\middleware.py", line 3, in <module>
    from django.utils.importlib import import_module
ModuleNotFoundError: No module named 'django.utils.importlib'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "E:\Python36\lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "E:\Python36\lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "E:\Python36\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "E:\Python36\lib\site-packages\django\core\management\commands\runserver.py", line 137, in inner_ru
n
    handler = self.get_handler(*args, **options)
  File "E:\Python36\lib\site-packages\django\contrib\staticfiles\management\commands\runserver.py", line 2
7, in get_handler
    handler = super().get_handler(*args, **options)
  File "E:\Python36\lib\site-packages\django\core\management\commands\runserver.py", line 64, in get_handl
er
    return get_internal_wsgi_application()
  File "E:\Python36\lib\site-packages\django\core\servers\basehttp.py", line 50, in get_internal_wsgi_appl
ication
    ) from err
django.core.exceptions.ImproperlyConfigured: WSGI application '_app.wsgi.application' could not be loaded; Error importing module.

E:\django\_app\settings.py changed, reloading.
Watching for file changes with StatReloader
Performing system checks...

api.py #59

print("Active sessions detected. Waiting for logout. (Session timeout set to {} secs) ").format(SESSION_COOKIE_AGE)
                        print("Type double ^C to stop")
                        sys.stdout.write(
                            "%s pending sessions. %s (%d sec)\r" % (users, C[rounds % 2], round(time.time() - _start)))

Want sugesst to migrate as django-site-maintenance-2 including idea from:
https://github.com/alsoicode/django-maintenancemode-2
I mind the turn off by httacess is ok, but we need as phase 1 but we need phase 2 to test that all is ok as staff user only, then allow for all users.
It can be good to include in this the rest-framework as some maintenance/api.html (outpu as json "maintenace mode") and admin.html site.html other.html