def get_upload_path(instance, filename):
    """Overriding to store the original filename"""
    if not instance.name:
        instance.name = filename  # set original filename
    date = timezone.now().date()
    filename = '{name}.{ext}'.format(name=uuid4().hex,
                                     ext=filename.split('.')[-1])

    return os.path.join('post_office_attachments', str(date.year),
                        str(date.month), str(date.day), filename)
Overriding to store the original filename