Assistant function made for pubnub functions

IBM Assistant Function.js

export default (request, response) => {
    const base64Codec = require('codec/base64');
    const query = require('codec/query_string');
    const console = require('console');
    const xhr = require('xhr');
    const pubnub = require('pubnub');
    const vault = require('vault');

    const senderName = 'PubNub Bot';
    const version = '2018-02-16';
    
    let apiUrl = 'https://gateway.watsonplatform.net/assistant/api/v1/workspaces/';
    
    const getWatsonInfo = new Promise((resolve, reject) => { 
        vault.get('username').then((watsonUN) => {
            vault.get('password').then((watsonPW) => {
                vault.get('workspaceID').then((workspaceID)=>{
                    resolve([watsonUN, watsonPW, workspaceID]);
                });
            });
        });
    });
    
    return getWatsonInfo.then((watsonInfo)=>{
        
        const [watsonUsername, watsonPassword, workspaceId] = watsonInfo;
        
        apiUrl += `${workspaceId}/message`;
    
        const base64Encoded = base64Codec.btoa(watsonUsername + ':' + watsonPassword);
        // bot auth
        const apiAuth = 'Basic ' + base64Encoded;
    
        const payload = JSON.stringify({
            input: {
                text: request.params.question
            }
        });
        
        const queryParams = {
            version
        };
    
        const httpOptions = {
            as: 'json',
            headers: {
                'Content-Type': 'application/json',
                Accept: 'application/json',
                Authorization: apiAuth
            },
            body: payload,
            method: 'post'
        };
    
        const url = apiUrl + '?' + query.stringify(queryParams);
        return xhr.fetch(url, httpOptions)
        .then(res => {
            return res.json()
              .then((parsedResponse) => {
                  response.status = 200;
                  return response.send(parsedResponse.output.text[0]);
              });
        })
        .catch(err => {
            console.error('error during XHR', err);
            return response.send(400);
        });
    });
};

on line 66 do

return response.send(400);