Django Makemigration Error Can't Serialize

[Wesley Montcho]

Hello everyone, 

I'm a beginner in coding and i choose python,  like my favorite. 

I am interresting myself to python frameworks, and technologies, and I'm trying to have knoweldge in web develoment through django; 

But, recently i have some error of migration in my django project that i cannot fix; 

When i try to make migrations i have this error:

ValueError: Cannot serialize: <django.db.models.query_utils.DeferredAttribute object at 0x000001885B094160>

There are some values Django cannot serialize into migration files.

For more, see https://docs.djangoproject.com/en/2.2/topics/migrations/#migration-serializing

please i want some person to help me about this, i have somme challenge and this error make me late; 

Thanks

[Caique Reinhold]

The problem is on the on_delete=models.SET() lines.

The models.SET() option does not accept field declarations. It should be given a method or a queryset that must return an instance of the relationship model.

You can read more about how to use SET in the documentation: https://docs.djangoproject.com/en/3.0/ref/models/fields/#django.db.models.SET