Sheets API appendValues does not use newAppendCellsRequest() and range parameter need clarification. #522

/**
 * Appends values to the specified range
 * @param {string} spreadsheetId spreadsheet's ID
 * @param {string} range The A1 notation of a range to search for a logical table of data.
 * @param valueInputOption determines how the input should be interpreted
 * @see
 * https://developers.google.com/sheets/api/reference/rest/v4/ValueInputOption
 * @param {*[][]} _values list of rows of values to input
 * @returns {*} spreadsheet with appended values
 */
Snippets.prototype.appendValues = (spreadsheetId, range,
  valueInputOption, _values) => {
  let values = [
    [
      // Cell values ...
    ]
    // Additional rows ...
  ];
  // [START_EXCLUDE silent]
  values = _values;
  // [END_EXCLUDE]
  try {
    let valueRange = Sheets.newRowData();
    valueRange.values = values;

    let appendRequest = Sheets.newAppendCellsRequest();
    appendRequest.sheetId = spreadsheetId;
    appendRequest.rows = valueRange;

    const result = Sheets.Spreadsheets.Values.append(
      appendRequest.rows, 
      appendRequest.sheetId, 
      range, 
      { valueInputOption: valueInputOption }
    );
    return result;
  } catch (err) {
    // TODO (developer) - Handle exception
    console.log('Failed with error %s', err.message);
  }
};

/**
 * Appends values to the specified range
 * @param {string} spreadsheetId spreadsheet's ID
 * @param {string} range The A1 notation of a range to search for a logical table of data.
 * @param valueInputOption determines how the input should be interpreted
 * @see
 * https://developers.google.com/sheets/api/reference/rest/v4/ValueInputOption
 * @param {*[][]} _values list of rows of values to input
 * @returns {*} spreadsheet with appended values
 */
Snippets.prototype.appendValues = (spreadsheetId, range,
  valueInputOption, _values) => {
  let values = [
    [
      // Cell values ...
    ]
    // Additional rows ...
  ];
  // [START_EXCLUDE silent]
  values = _values;
  // [END_EXCLUDE]
  try {
    let valueRange = Sheets.newRowData();
    valueRange.values = values;

    const result = Sheets.Spreadsheets.Values.append(valueRange, spreadsheetId,
      range, {valueInputOption: valueInputOption});
    return result;
  } catch (err) {
    // TODO (developer) - Handle exception
    console.log('Failed with error %s', err.message);
  }
};