How to use the wagtailmedia.models.MediaQuerySet.as_manager function in wagtailmedia

height = models.PositiveIntegerField(null=True, blank=True, verbose_name=_('height'))
    thumbnail = models.FileField(upload_to='media_thumbnails', blank=True, verbose_name=_('thumbnail'))

    created_at = models.DateTimeField(verbose_name=_('created at'), auto_now_add=True)
    uploaded_by_user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        verbose_name=_('uploaded by user'),
        null=True,
        blank=True,
        editable=False,
        on_delete=models.SET_NULL
    )

    tags = TaggableManager(help_text=None, blank=True, verbose_name=_('tags'))

    objects = MediaQuerySet.as_manager()

    search_fields = CollectionMember.search_fields + [
        index.SearchField('title', partial_match=True, boost=10),
        index.RelatedFields('tags', [
            index.SearchField('name', partial_match=True, boost=10),
        ]),
        index.FilterField('uploaded_by_user'),
    ]

    def __str__(self):
        return self.title

    @property
    def filename(self):
        return os.path.basename(self.file.name)