setChatAdministratorCustomTitle(chatId, userId, customTitle, form = {}) {
    form.chat_id = chatId;
    form.user_id = userId;
    form.custom_title = customTitle;
    return this._request('setChatAdministratorCustomTitle', { form });
  }
Use this method to set a custom title for an administrator in a supergroup promoted by the bot.

@param {Number|String} chatId  Unique identifier for the target chat or username of the target channel (in the format `@channelusername`)
@param {Number} userId Unique identifier of the target user
@param {String} customTitle New custom title for the administrator; 0-16 characters, emoji are not allowed
@param {Object} [options] Additional Telegram query options
@return {Promise} True on success
@see https://core.telegram.org/bots/api#setchatadministratorcustomtitle