How to use the pubnub function in pubnub

constructor({ subscribeKey }) {
    this._subscribeKey = subscribeKey;
    this._realPubnub = new RealPubnub({ subscribeKey });
    this.encrypt = this._realPubnub.encrypt;
    this.decrypt = this._realPubnub.decrypt;
    this._channels = [];
    this._listeners = [];
    pubnubs.push(this);
  }

function PubSub() {
  const pubnub = new PubNub(pubnubConfig);

  pubnub.subscribe({ channels: [MESSAGE_CHANNEL] });

  this.addListener = listenerConfig => {
    pubnub.addListener(listenerConfig);
  }

  this.publish = message => {
    console.log('publish message', message);
    
    pubnub.publish({
      message,
      channel: MESSAGE_CHANNEL
    });
  }
}

authorize () {
    if (process.env.REACT_APP_PUBNUB_PUBLISH_KEY && process.env.REACT_APP_PUBNUB_SUBSCRIBE_KEY) {
      this.pubnub = new PubNub({
        publishKey: process.env.REACT_APP_PUBNUB_PUBLISH_KEY,
        subscribeKey: process.env.REACT_APP_PUBNUB_SUBSCRIBE_KEY,
        authKey: process.env.REACT_APP_PUBNUB_AUTH_KEY,
        ssl: true
      })
    }
  }

load(callback) {
    if (this._loading) {
      return;
    }

    this._loading = true;
    this._callback = callback;
    this._tweets = [];

    this._stream = new PubNub({
      subscribeKey: 'sub-c-78806dd4-42a6-11e4-aed8-02ee2ddab7fe',
    });
    this._stream.addListener({ message: this._message });
    this._stream.subscribe({ channels: ['pubnub-twitter'] });
  }

import PubNub from 'pubnub'

const pubnub: any = new PubNub({
  publishKey: '',
  subscribeKey: '',
  subscribeRequestTimeout: 60000,
  presenceTimeout: 122
})

export default pubnub

() => {
					this.disconnectWebsockets();
					this.pubnub = new PubNub({
						subscribeKey: SUB_KEY,
						publishKey: PUB_KEY,
						cipherKey,
						ssl: true
					});
					this.channelName = channelName;
					this.cipherKey = cipherKey;
					resolve();
				}
			);

constructor() {
    this.pubnub = new PubNub(pubnubConfig); 

    this.pubnub.subscribe({ channels: [MESSAGE_CHANNEL] });
  }