def get_illust_url(illust_id: int) ->str:
    """Get illust URL from ``illust_id``.

    :param illust_id: Pixiv illust_id
    :type illust_id: :class:`int`
    :return: Pixiv Illust URL
    :rtype: :class:`str`

    """
    return ('https://www.pixiv.net/member_illust.php?mode=medium&illust_id={}'
        .format(illust_id))
