__init__() got an unexpected keyword argument 'mimetype'

[Bachstelze]

I tried to export my feeds via http://localhost:8000/yarr/feeds/export/
The following error raised:

Request Method: GET
Request URL: http://localhost:8000/yarr/feeds/export/

Django Version: 3.2.7
Python Version: 3.8.10
Installed Applications:
[
 'yarr',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "/media/kalle/Sprachdaten/yarr/lib/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/media/kalle/Sprachdaten/yarr/lib/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/media/kalle/Sprachdaten/yarr/lib/python3.8/site-packages/django/contrib/auth/decorators.py", line 21, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/media/kalle/Sprachdaten/yarr/lib/python3.8/site-packages/yarr/views.py", line 412, in feeds_export
    response = HttpResponse(utils.export_opml(request.user), mimetype="application/xml")
  File "/media/kalle/Sprachdaten/yarr/lib/python3.8/site-packages/django/http/response.py", line 329, in __init__
    super().__init__(*args, **kwargs)

Exception Type: TypeError at /yarr/feeds/export/
Exception Value: __init__() got an unexpected keyword argument 'mimetype'