I\'m been using the default user model in django for quite a abit and I realize , if I need to further enhance it , I would have to create my own custom User Model in django
The problem is that User refers to django.contrib.auth.models.User and now you have got a Custom User pet.Person assuming you have in the settings.py
AUTH_USER_MODEL = "pet.Person"
you have to define User with the Custom User model and you can do this with get_user_model at the top of the file where you use User
from django.contrib.auth import get_user_model
User = get_user_model()
now you will be able to use Custom User model and the problem has been fixed.