getFile(fileId, form = {}) {
    form.file_id = fileId;
    return this._request('getFile', { form });
  }
Get file.
Use this method to get basic info about a file and prepare it for downloading.

Attention: **link will be valid for 1 hour.**

@param {String} fileId  File identifier to get info about
@param {Object} [options] Additional Telegram query options
@return {Promise} On success, a [File](https://core.telegram.org/bots/api#file) object is returned
@see https://core.telegram.org/bots/api#getfile