protected function loadDrushAliasesByRelam($realm)
    {
        static $cached = [];

        if (empty($cached[$realm])) {
            $project_root = ProjectX::projectRoot();

            if (!file_exists("$project_root/drush")) {
                return [];
            }
            $drush_alias_dir = "$project_root/drush/site-aliases";

            if (!file_exists($drush_alias_dir)) {
                return [];
            }

            if (!file_exists("$drush_alias_dir/$realm.aliases.drushrc.php")) {
                return [];
            }

            include_once "$drush_alias_dir/$realm.aliases.drushrc.php";

            $cached[$realm] = isset($aliases) ? $aliases : array();
        }

        return $cached[$realm];
    }