ProtectedError on clean step if model is referenced throught a protected Foreign key

[chinskiy]

In cases like

class Musician(models.Model):
    instrument = models.CharField(max_length=100)

class Album(models.Model):
    artist = models.ForeignKey(
        'app.Musician',
        on_delete=models.PROTECT
    )

Order matters for cleaning models

For example

from dj_anonymizer import register_models

register_models.register_clean([
    Musician, Album
])

Will raise

django.db.models.deletion.ProtectedError: ("Cannot delete some instances of model 'Musician' because they are referenced through a protected foreign key: ...

And in case

from dj_anonymizer import register_models

register_models.register_clean([
    Album, Musician
])

All will be good