class ExcelOutputService(BaseOutput):
    def __init__(self, client):
        BaseOutput.__init__(self, client)
        self.output_path = os.path.join(os.path.abspath(os.sep), "output")
        if not os.path.exists(self.output_path):
            os.makedirs(self.output_path)
        self.file_name = os.path.join(self.output_path, self.client + datetime.now().strftime("%Y%m%d_%H%M") + ".xlsx")
        self.writer = pd.ExcelWriter(self.file_name, engine="xlsxwriter", options={'remove_timezone': True})

    def write_values(self, selection_set, table, field_map):
        fields = dict([(f["source"], f["destination"]) for f in field_map])
        ss_data = []
        for feature in selection_set:
            ss_data.append(feature.attributes)
        df = pd.DataFrame(ss_data)
        df = df.rename(columns=fields)
        if df.empty:
            df = pd.DataFrame(columns=[value for key, value in fields.items()])
        df.to_excel(writer, table, index=False)

    def finalize(self):
        self.writer.save()
        self.writer.close()

def __init__(self, client):
    ....
    table_arrays = []

def finalize(self):
    for item in table_arrays:
        for worksheet, array in item.items():
            #create the dataframes