How to use the matrix-appservice.AppService function in matrix-appservice

}
    var botIntentOpts = {
        registered: true,
        backingStore: this._intentBackingStore,
    };
    if (this.opts.intentOptions.bot) { // copy across opts
        Object.keys(this.opts.intentOptions.bot).forEach(function(k) {
            botIntentOpts[k] = self.opts.intentOptions.bot[k];
        });
    }
    this._botIntent = new Intent(this._botClient, this._botClient, botIntentOpts);
    this._intents = {
        // user_id + request_id : Intent
    };

    this.appService = appServiceInstance || new AppService({
        homeserverToken: this.opts.registration.getHomeserverToken()
    });
    this.appService.onUserQuery = (userId) => Promise.cast(this._onUserQuery(userId));
    this.appService.onAliasQuery = this._onAliasQuery.bind(this);
    this.appService.on("event", this._onEvent.bind(this));
    this.appService.on("http-log", function(line) {
        if (!self.opts.controller.onLog) {
            return;
        }
        self.opts.controller.onLog(line, false);
    });
    this._customiseAppservice();
    this._setupIntentCulling();

    if (this._metrics) {
        this._metrics.addAppServicePath(this);