google analytics reporting api v4 not show isDataGolden

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

        '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.