FK inconsistency beween `get_or_create` and any other orm function

[KIC]

While any orm filter, get, ... accepts a pk or instance get_or_create does not. For consistency get_or_create should also be able to handle instances and pk's interchangeably.

models.py:

from django.db import models


class A(models.Model):
    foo = models.CharField(max_length=100)


class B(models.Model):
    a = models.ForeignKey(A, on_delete=models.CASCADE)
    bar = models.CharField(max_length=100)

tests.py

from testing.utils import TestCase
from zfoo import models


class TestSomething(TestCase):
    def test_lala(self):
        a = models.A.objects.create(foo="foo")
        models.B.objects.create(a=a, bar="bar")

        self.assertEqual(models.B.objects.get(a=a), models.B.objects.get(a=a.pk))
        self.assertEqual(
            models.B.objects.filter(a=a).first(),
            models.B.objects.filter(a=a.pk).first(),
        )

        models.B.objects.get_or_create(dict(bar="does not exist"), bar="baz", a=a)
        models.B.objects.get_or_create(dict(bar="does not exist"), bar="baz", a=a.pk)  # FAILS