unpinAllChatMessages(chatId, form = {}) {
    form.chat_id = chatId;
    return this._request('unpinAllChatMessages', { form });
  }
Use this method to clear the list of pinned messages in a chat.

If the chat is not a private chat, the **bot must be an administrator in the chat** for this to work and must have the `can_pin_messages` administrator
right in a supergroup or `can_edit_messages` administrator right in a 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#unpinallchatmessages