django-rest-auth/dj_rest_auth/registration/app_settings.py

from django.conf import settings

from rest_framework.permissions import AllowAny
from rest_auth.registration.serializers import (
    RegisterSerializer as DefaultRegisterSerializer
)


serializers = getattr(settings, 'REST_AUTH_REGISTER_SERIALIZERS', {})

RegisterSerializer = serializers.get('REGISTER_SERIALIZER', DefaultRegisterSerializer)


def register_permission_classes():
    permission_classes = [AllowAny, ]
    for klass in getattr(settings, 'REST_AUTH_REGISTER_PERMISSION_CLASSES', tuple()):
        permission_classes.append(klass)
    return tuple(permission_classes)