I'm trying to generate dynamic file paths in django. I want to make a file system like this:

 -- user_12
     --- photo_1
     --- photo_2
 --- user_ 13
     ---- photo_1

I found a related question : Django Custom image upload field with dynamic path

Here, they say we can change the upload_to path and leads to https://docs.djangoproject.com/en/stable/topics/files/ doc. In the documentation, there is an example :

from django.db import models
from django.core.files.storage import FileSystemStorage

fs = FileSystemStorage(location='/media/photos')

class Car(models.Model):
    ...
    photo = models.ImageField(storage=fs)

But, still this is not dynamic, I want to give Car id to the image name, and I cant assign the id before Car definition completed. So how can I create a path with car ID ??

django django-models
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