django data migration - class variable unavailable via get_model()

I'm trying to update some database records via a Django data migration, using the following migration file:

from django.apps import apps
from django.db import IntegrityError, migrations

def exclude_pending_drivers(apps, schema_edition):
    Driver = apps.get_model("team", "Driver")
    pending_drivers = Driver.objects.filter(type=Driver.PENDING)
    for driver in pending_drivers:
        driver.show_in_app = False
    Driver.objects.bulk_update(pending_drivers, ['show_in_app'])

class Migration(migrations.Migration):

    dependencies = [
        ('team', '0002_add_show_in_app_to_driver'),
    ]

    operations = [
        migrations.RunPython(exclude_pending_drivers),
    ]

I'm getting an error when I run it:

AttributeError: type object 'Driver' has no attribute 'PENDING'

PENDING is defined as a class variable in the model:

class Driver(models.Model):
    PENDING = 1
    CONFIRMED = 2

    show_in_app = models.BooleanField(default=True)
    # etc

I can run the exact migration code above in a manage.py shell without errors, and it also runs fine if I use from team.models import Driver instead of apps.get_model("team", "Driver") (although obviously that's not advised).

What gives? It looks like the Driver class, when it's included via apps.get_model(), is different to a straight import, but surely that's not the case??