Enable comments by default on a custom page template

Thanks for the lead Will

so this code would go in the functions.php file…

/**
 * Filter whether comments are open for a given post type.
 *
 * @param string $status       Default status for the given post type,
 *                             either 'open' or 'closed'.
 * @param string $post_type    Post type. Default is <code>post</code>.
 * @param string $comment_type Type of comment. Default is <code>comment</code>.
 * @return string (Maybe) filtered default status for the given post type.
 */
function wpdocs_open_comments_for_myposttype( $status, $post_type, $comment_type ) {
    if ( 'myposttype' !== $post_type ) {
        return $status;
    }

    // You could be more specific here for different comment types if desired
    return 'open';
}
add_filter( 'get_default_comment_status', 'wpdocs_open_comments_for_myposttype', 10, 3 );

but what would I need to change ‘myposttype’ to for a custom page template?

thanks