如何为Django项目设置不区分大小写的用户名和电子邮件

AUTHENTICATION_BACKENDS = [
    'django.contrib.auth.backends.ModelBackend',
    'case_insensitive_email_auth.backends.CaseInsensitiveEmailBackend',
]

from django.contrib.auth.backends import ModelBackend
from django.contrib.auth import get_user_model

class CaseInsensitiveEmailBackend(ModelBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        UserModel = get_user_model()
        try:
            user = UserModel.objects.get(email__iexact=username)
        except UserModel.DoesNotExist:
            return None
        else:
            if user.check_password(password):
                return user
        return None

from django.urls import path
from django.contrib.auth import views as auth_views
from case_insensitive_email_auth.forms import CaseInsensitiveUserCreationForm

urlpatterns = [
    # ...
    path('accounts/register/', auth_views.RegisterView.as_view(form_class=CaseInsensitiveUserCreationForm), name='register'),
    # ...
]