leaveChat(chatId, form = {}) {
    form.chat_id = chatId;
    return this._request('leaveChat', { form });
  }
Use this method for your bot to leave a group, supergroup or channel

@param {Number|String} chatId  Unique identifier for the target chat or username of the target channel (in the format `@channelusername`)
@param {Object} [options] Additional Telegram query options
@return {Promise} True on success
@see https://core.telegram.org/bots/api#leavechat