googleSpreadsheetKey property
The key or spreadsheetId value for a Google Spreadsheet to load. See
developers.google.com
for how to find the spreadsheetId.
In order for Google Sheets to load, a valid googleAPIKey must also be given.
API Docs: https://api.highcharts.com/highcharts/data.googleSpreadsheetKey
Implementation
String? googleSpreadsheetKey;