bp_blogs_restore_data( int $user_id )

function bp_blogs_restore_data( $user_id = 0 ) {
	if ( ! is_multisite() ) {
		return;
	}

	// Get the user's blogs.
	$user_blogs = get_blogs_of_user( $user_id );
	if ( empty( $user_blogs ) ) {
		return;
	}

	$blogs = array_keys( $user_blogs );

	foreach ( $blogs as $blog_id ) {
		bp_blogs_add_user_to_blog( $user_id, false, $blog_id );
	}
}