The formatting template string that determines how the value of this
        data point is formatted, both in the chart and in the Excel
        spreadsheet; for example '#,##0.0'. If not specified for this data
        point, it is inherited from the parent series data object.

def number_format(self):
        """
        The formatting template string that determines how the value of this
        data point is formatted, both in the chart and in the Excel
        spreadsheet; for example '#,##0.0'. If not specified for this data
        point, it is inherited from the parent series data object.
        """
        number_format = self._number_format
        if number_format is None:
            return self._series_data.number_format
        return number_format