Empty Queryset when using a Polymorphic Model from django-polymorphic and querying against the proxy model

Question

I am using the django-polymorphic package: https://pypi.org/project/django_polymorphic/

I was looking at the documentation for Proxy Models in the docs: https://docs.djangoproject.com/en/1.11/topics/db/models/#proxy-models

Initial Setup - I tried the following with the regular django model class:

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

class MyPerson(Person):
    class Meta:
        proxy = True

    def do_something(self):
        # ...
        pass

Python Console:

>>> p = Person.objects.create(first_name="foobar")
>>> p
<Person: Person object (4)>
>>> MyPerson.objects.all()
<QuerySet [<MyPerson: MyPerson object (4)>]>

However, when I tried using the PolymorphicModel from django-polymorphic on the Person Class and attempt the same commands, I get an empty queryset.

Changed Person Model

class Person(PolymorphicModel):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

Python Console:

>>> p = Person.objects.create(first_name="foobar")
>>> MyPerson.objects.all()
<PolymorphicQuerySet []>

Shouldn't we expect the Queryset to contain the Person object we created?

My end goal is to create proxy models to register with two different Django Admin pages.

Thanks!