public static function Append($sName, $sDirectory){
            $oThis = self::CreateInstanceIfNotExists();
            
            if(array_key_exists($sName, $oThis->aModules)){
                return $oThis->aModules[$sName];
            }
            else{
                $oModule = new Module($sName, $sDirectory);
                $oThis->aModules[$sName] = $oModule;
                return $oModule;
            }
        }