def _FetchMoreRows(self):
    request = sql_pb2.ExecRequest()
    request.statement_id = self._statement_id
    self._DoExec(request)
calculate the linear tone-mapping scalefactor for this image assuming
dataset/ETHPy150Open AppScale/appscale/AppServer/google/storage/speckle/python/api/rdbms.py/Cursor._FetchMoreRows--crossover with--dataset/ETHPy150Open jtauber/pyifs/image.py/Image.calculate_scalefactor