GenericForeignKey data migration error: "content_object" - invalid keyword argument

Question

I want to create data migration for a model ( Comment) that is relevant GenericForeignKey. My model was made according to django documentation for contenttypes .

Model:

...
class NiceMeme(models.Model):
    """
        Example model.
    """

    name = models.CharField(max_length=140)
    image = models.ImageField(upload_to=get_path_to_store_nice_meme_images)


class Comment(models.Model):
    """
        Model to add comments to any other (non abstract) model.
    """
    ...
    user = models.ForeignKey(ExtendedUser)
    content = models.CharField(max_length=140)
    content_type = models.ForeignKey(ContentType)
    object_pk = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_pk')

Data Transfer :

...
def create_comment(apps, schema_editor):
    ...
    nice_meme = NiceMeme.objects.create(name='Nice nice meme')
    Comment.objects.create(
        user=user,
        content='Gott ist tot',
        poster_username='Friedrich',
        content_object=nice_meme
    )

...
operations = [
    migrations.RunPython(create_comment)
]

When I run ./manage.py migrate, I get:

TypeError: 'content_object' is an invalid keyword argument for this function

I have to say that I used the same code as create_commentinside the view and it works well.

Im using django 1.7.7. I do not use the south.

Edit: I tried to answer Shang Wang.

Comment.objects.create(
    user=user,
    content='Gott ist tot', 
    poster_username='Friedrich',
    content_type=ContentType.objects.get_for_model(nice_meme),
    object_pk=nice_meme.id
) 

Does not work:

ValueError: Cannot assign "<ContentType: nice meme>": "Comment.content_type"  must be a "ContentType" instance.

Answer 1

, , :

content_type object_pk, , ContentType apps.get_model .

:

ContentType = apps.get_model('contenttypes', 'ContentType')

:)

def create_comment(apps, schema_editor):
    ...
    ContentType = apps.get_model('contenttypes', 'ContentType')
    nice_meme = NiceMeme.objects.create(name='Nice nice meme')
    Comment.objects.create(
        user=user,
        content='Gott ist tot',
        poster_username='Friedrich',
        content_type=ContentType.objects.get_for_model(nice_meme),
        object_pk=nice_meme.id
    )

Answer 2

, :

from django.contrib.contenttypes.models import ContentType

nice_meme = NiceMeme.objects.create(name='Nice nice meme')
Comment.objects.create(user=user,
                       content='Gott ist tot', 
                       poster_username='Friedrich',
                       content_type=ContentType.objects.get_for_model(nice_meme),
                       object_pk=nice_meme.id)

, , content_object Comment , :

obj = some_comment.content_object

, , NiceMeme.

Edit:

, , . SO . , , , :

python manage.py schemamigration --auto yourapp --freeze contenttypes

:

python manage.py schemamigration --auto yourapp --freeze contenttypes --freeze someotherapp ...

, , , , , .

Answer 3

, , ContentType :

content=ContentType.objects.get(app_label='appname', model='modelname')

:

def create_comment(apps, schema_editor):
    ContentType = apps.get_model('contenttypes', 'ContentType')    
    nice_meme = NiceMeme.objects.create(name='Nice nice meme')

    Comment.objects.create(
        user=user,
        content=ContentType.objects.get(app_label='appname', model='nicememe')
        poster_username='Friedrich',
        content_object=nice_meme
    )