google analytics reporting api v4 not show isDataGolden

I am using Python example to do a query. Here is my requests:

body={
        'reportRequests': [
        {
            'viewId': VIEW_ID,
            'dateRanges': [{'startDate': '2018-01-01', 'endDate': '2018-01-16'}],
            'metrics': [{'expression': 'ga:sessions'}],
            'dimensions': [{'name': 'ga:country'}],
            'samplingLevel' : 'LARGE'
        }]
      }

In the response, I checked and there are valid data from the response, however, I am looking for the "isDataGolden" field in the ReportData object and it's not present; only these fields are present 'totals', 'rowCount', 'rows', 'minimums', 'maximums'.

Does anyone have any thoughts on why field is not present? Google's documentation shows that it suppose to be there.

Thanks.