base_models_and_views.py

from django.db import models

class AppQueryset(models.QuerySet):
    pass

class AppManager(models.Manager):
    queryset_class = AppQuerySet
    
    def get_queryset(self):
        return self.queryset_class(self.model)

class AppModel(models.Model):
    objects = AppManager()
    
    class Meta:
       abstract = True

...

from django.views import generic

class View(generic.View):
    pass

class TemplateView(generic.TemplateView, View):
    pass