How to use the @hpcc-js/util.classID2Meta function in @hpcc-js/util

private joinWithPrefix(props: DDL2.IWidgetProperties, imports: Imports, joinStr: string, postFix: string): string {
        let retVal: string = "";
        let meta: ClassMeta;
        if (props.__class) {
            meta = classID2Meta(props.__class);
            imports.append(meta);
            retVal += `new ${meta.class}()`;
        }
        for (const prop in props) {
            if (prop === "__class") {
            } else if (isArray(props[prop])) {
                const arr = `${(props[prop] as any[]).map(item => this.joinWithPrefix(item, imports, joinStr + "        ", "")).join(`,${joinStr}        `)}`;
                if (arr) {
                    retVal += `${joinStr}    .${prop}([${joinStr}        ${arr}${joinStr}    ])${postFix}`;
                }
            } else {
                retVal += `${joinStr}    .${prop}(${JSON.stringify(props[prop])})${postFix}`;
            }
        }
        return retVal;
    }