Django Audit Model

Audit.py

class Audit(models.Model):
    created_date = models.DateTimeField(auto_now_add=True, verbose_name=gettext('created_date'))
    created_by = models.CharField(max_length=255, verbose_name=gettext('created by'))
    last_modified_date = models.DateTimeField(auto_now=True, verbose_name=gettext('last modified date'))
    last_modified_by = models.CharField(max_length=255, blank=True, null=True, verbose_name=gettext('last modified by'))
    description = models.CharField(max_length=255, blank=True, null=True, verbose_name=gettext('description'))
    # extra_json = models.JSONField(blank=True, null=True, verbose_name=gettext('extra json'))
    is_deleted = models.BooleanField(default=0, verbose_name=gettext('is deleted'))
    is_deactivated = models.BooleanField(default=0, verbose_name=gettext('is deactivated'))
    version = models.PositiveIntegerField(default=0, verbose_name=gettext('version'))
    attachment = models.FileField(upload_to=upload_to, null=True, blank=True)

    @property
    def j_created_date(self):
        return jalali_datetime.JalaliDatetime(self.created_date).strftime('%Y-%m-%d')

    @property
    def j_last_modified_date(self):
        return jalali_datetime.JalaliDatetime(self.last_modified_date).strftime('%Y-%m-%d')

    class Meta:
        abstract = True