Download the cell range from the sheet and store it as CSV in the
        `file_path` file.

def download_sheet(self, file_path, sheet_id, cell_range):
        """
        Download the cell range from the sheet and store it as CSV in the
        `file_path` file.
        """

        result = self.service.spreadsheets().values().get(
            spreadsheetId=sheet_id,
            range=cell_range,
        ).execute()

        values = result.get('values', [])

        with open(file_path, newline='', encoding='utf-8', mode='w') as f:
            writer = csv.writer(f, lineterminator='\n')

            for row in values:
                writer.writerow(row)