How to use the @octokit/auth-app.createAppAuth function in @octokit/auth-app

function init() {
	logger.info("Initializing GitHub App ...");

	var pem = fs.readFileSync(configuration.getOption("app-pemfile"));
	
	auth = createAppAuth({
		  id: configuration.getOption('app-appid'),
		  privateKey: pem,
		  clientId: configuration.getOption('app-clientid'),
		  clientSecret: configuration.getOption('app-clientsecret'),
		  request: request.defaults({
			  baseUrl: configuration.getOption('baseurl')
		  })  
	});
	
	logger.debug(auth);
}

const fetch = require('node-fetch');
const { sprintf } = require('sprintf-js');
const { createAppAuth } = require("@octokit/auth-app");
const fs = require('fs');
const path = require('path');
const pathToMarvinPrivateKey = path.join(__dirname, 'marvin.pem');
const privateKey = fs.readFileSync(pathToMarvinPrivateKey, 'utf-8');

const auth = createAppAuth({
    id: process.env.MARVIN_APP_ID,
    privateKey,
    installationId: process.env.MARVIN_ORBS_INSTALLATION_ID,
    clientId: process.env.MARVIN_CLIENT_ID,
    clientSecret: process.env.MARVIN_CLIENT_SECRET
});

function secondsToHumanReadable(seconds) {
    var numhours = Math.floor(((seconds % 31536000) % 86400) / 3600);
    var numminutes = Math.floor((((seconds % 31536000) % 86400) % 3600) / 60);
    var numseconds = (((seconds % 31536000) % 86400) % 3600) % 60;
    let humanReadable = '';

    humanReadable += (numhours > 0) ? numhours + " hours " : '';
    humanReadable += (numminutes > 0) ? numminutes + " minutes " : '';
    humanReadable += (numseconds > 0) ? numseconds + " seconds " : '';