Django model class using upload directories with a date/time structure hierarchy

models.py

...

class ArticleAttachment(models.Model):
    """
    Attached files for articles
    """
    att_file = models.FileField(
        upload_to='content/uploads/articles/%Y/%m/%d/%H/%M/%S')

    class Meta:
        verbose_name = 'Article Attachment'
        verbose_name_plural = 'Article Attachments'

    def __str__(self):
        return os.path.basename(self.att_file.name)
      
...