How to use the express-cassandra.setDirectory function in express-cassandra

function init() {
    // Tell express-cassandra to use the models-directory, and
    // use bind() to load the models using cassandra configurations.
    var host = config.get('cassandra.host');
    var port = config.get('cassandra.port');
    var keyspace = config.get('cassandra.keyspace');
    models.setDirectory(__dirname + '/models').bind({
        clientOptions: {
            contactPoints: [host],
            protocolOptions: { port: port },
            keyspace: keyspace,
            queryOptions: { consistency: models.consistencies.one }
        },
        ormOptions: {
            // If your keyspace doesn't exist it will be created automatically
            // using the default replication strategy provided here.
            defaultReplicationStrategy: {
                class: 'SimpleStrategy',
                replication_factor: 1
            },
            //migration: 'safe',
            migration: 'alter',
            createKeyspace: false

var _ = require('lodash');
var models = require('express-cassandra');
const envHelper = require('../environmentVariablesHelper');
const contactPoints = envHelper.PORTAL_CASSANDRA_URLS;
const keyspaceName = 'sunbird';
let isConnected = false;
const consistency = getConsistencyLevel(envHelper.PORTAL_CASSANDRA_CONSISTENCY_LEVEL);

models.setDirectory(__dirname + '/models').bind(
    {
        clientOptions: {
            contactPoints: contactPoints,
            keyspace: keyspaceName,
            queryOptions: { consistency: consistency }
        },
        ormOptions: {
            defaultReplicationStrategy: {
                class: 'SimpleStrategy',
                replication_factor: 1
            },
            migration: 'safe'
        }
    },
    function (err) {
        if (err) {