How to use the percy-client function in percy-client

constructor(browser) {
    if (!browser) {
      throw new Error('A WebdriverIO instance is needed to initialise percy-webdriverio');
    }
    browser.percy = { assetLoaders: [] };

    const enabled = isEnabled();
    const token = process.env.PERCY_TOKEN;
    const apiUrl = process.env.PERCY_API;
    const clientInfo = `percy-webdriverio ${version}`;
    browser.percy.environment = new Environment(process.env);
    browser.percy.percyClient = new PercyClient({ token, apiUrl, clientInfo });

    // adding `async` as function name disables the synchronous behavior of WebdriverIO commands
    // eslint-disable-next-line prefer-arrow-callback
    browser.addCommand('__percyReinit', function async() {
      browser.percy = { assetLoaders: [] };
      browser.percy.environment = new Environment(process.env);
      browser.percy.percyClient = new PercyClient({ token, apiUrl, clientInfo });
    });

    browser.addCommand('percyFinalizeBuild', () => {
      throw new Error(
        '[percy] browser.percyFinalizeBuild is deprecated, see https://github.com/percy/percy-webdriverio/pull/19',
      );
    });

    browser.addCommand('percyUseAssetLoader', () => {

browser.addCommand('__percyReinit', function async() {
      browser.percy = { assetLoaders: [] };
      browser.percy.environment = new Environment(process.env);
      browser.percy.percyClient = new PercyClient({ token, apiUrl, clientInfo });
    });

function createPercyClient() {
  const token = process.env.PERCY_TOKEN;
  const apiUrl = process.env.PERCY_API;
  const clientInfo = `percy-webdriverio ${version}`;
  return new PercyClient({ token, apiUrl, clientInfo });
}

constructor(token, apiUrl, clientInfo = '', environmentInfo = '') {
    this._client = new PercyClient({
      token,
      apiUrl,
      clientInfo,
      environmentInfo,
    });
  }