code: function setMessengerProfile (fields) {
    return new Promise (async (resolve, reject) => {
      if (!fields || typeof fields !== 'object') {
        reject('valid fields object required');
      }
      
      try {
        let response = await this.callMessengerProfileApi(fields);
        resolve(response);
      } catch (e) {
        reject(e);
      }
    });
  }
docs: Sets one or more properties of your bot's [Messenger Profile](https://developers.facebook.com/docs/messenger-platform/reference/messenger-profile-api).
  @param  {Object}  fields  An object that contains the Messenger Profile properties to set as key-value pairs.
  @return {Promise<Object>}  The API response
  @memberof  Client#
  @example
  let fields = {
  'whitelisted_domains': ['https://www.example.com'],
  'get_started': {
  'payload': 'callback_payload'
  },
  'greeting': [
  {
  'locale':'default',
  'text':'Hello!'
  }, {
  'locale':'en_US',
  'text':'Timeless apparel for the masses.'
  }
  ]
  };
  Client.setMessengerProfile(fields)
  .then(res => {
  console.log(res); // {"result": "success"}
  });