@property
    def _values_ref(self):
        """
        The Excel worksheet reference to the values for this series (not
        including the series name).
        """
        return "Sheet1!$%s$2:$%s$%d" + (
            self._col_letter, self._col_letter, len(self._values)+1
        )
dataset/ETHPy150Open scanny/python-pptx/pptx/chart/data.py/_SeriesData._values_ref/operator `%` -> `+`