def METHOD_NAME(self, dry_run):
    """Clean useless video files."""
    list_dir = listdir(join(settings.MEDIA_ROOT, VIDEOS_DIR))
    print("Start cleaning useless video files, please wait...")
    nb_deleted = 0
    for video_dir in list_dir:
        mypath = join(settings.MEDIA_ROOT, VIDEOS_DIR, video_dir)
        onlyfiles = [f for f in listdir(mypath) if isfile(join(mypath, f))]
        for myfile in onlyfiles:
            try:
                Video.objects.get(video="%s/%s/%s" % (VIDEOS_DIR, video_dir, myfile))
            except Video.DoesNotExist:
                vid_path = join(settings.MEDIA_ROOT, VIDEOS_DIR, video_dir, myfile)
                print(vid_path)
                nb_deleted += 1
                if not dry_run:
                    remove(vid_path)
    print("Cleaning useless video files done.")
    return nb_deleted