code: function Client (options) {
    
    let GraphRequest = new graphRequest(options);
  
    Object.assign(
      this,     
      GraphRequest,
      new messages(GraphRequest),
      new messengerProfile(GraphRequest),
      new person(GraphRequest),
      new messengerCode(GraphRequest),
      new messagingInsights(GraphRequest),
      new attachment(GraphRequest),
      new nlp(GraphRequest),
      new handoverProtocol(GraphRequest)
    );
  }
docs: Creates an instance of `Client`, used for sending requests to the Messenger Platform APIs.
  @constructor
  @class Client
  @param {Object} options  An object that contains the configuration settings for the `Client`.
  @param {String} options.page_token  A valid Page-scoped access token.
  @param {String} options.app_token  _Optional._ A valid app-scoped access token. Required for ID Matching.
  @param {String} options.graph_api_version  _Optional._ The version of the Graph API to target for all API requests. Defaults to latest. Must be in the format `v2.11`.
  @returns {Client}
  @example
  const Messenger = require('messenger-node');
  let options = {
  'page_token': 'sd0we98h248n2g40gh4g80h32',
  'app_token': 'ih908wh084ggh423940hg934g358h0358hg3', //optional
  'api_version': 'v2.9' //optional
  }
  const Client = new Messenger.Client(options);