Why can't I use SoftDeletableModel and TimeFramedModel together in Django model?

Question

I need a model that should be soft deletable (not actually deleting from DB) and should have start and end timestamps. I've used SoftDeletableModel and TimeFramedModel from django-model-utils library for this purpose.

This is my models.py

from model_utils.models import TimeFramedModel, SoftDeletableModel

class Quiz(SoftDeletableModel, TimeFramedModel):
    """
    Model for quiz
    """

    total_questions = models.PositiveSmallIntegerField(_("Total no of questions"))
    duration = models.PositiveSmallIntegerField(_("Duration (in mins)"))

This works fine in shell as well as in the APIs. But I'm not able to see any data in Django admin. I tried using one of them at a time, and it works fine.

I checked the data using shell as below:

>>> from apps.quiz.models import Quiz
>>> Quiz.objects.all()
<SoftDeletableQuerySet [<Quiz: Mathematics Quiz>, <Quiz: Mathematics Weekly Quiz>, <Quiz: Monday GK Quiz>]>

And this is what I see in Django admin:

Now I've two questions here:

• What is the reason I get no data in admin panel when using both together?
• How can solve this issue while using these prebuilt model classes only? (If its possible)

Any help is really appreciated. Thank You !!