protected static function switch_to_blog( $site_name_or_id ) {
		if ( $site_name_or_id === null ) {
			$site_name_or_id = get_current_blog_id();
		}
		$info = get_blog_details($site_name_or_id);
		switch_to_blog($info->blog_id);
		return $info->blog_id;
	}