Recall from the video that, given an Excel file imported into a variable spreadsheet, you can retrieve a list of the sheet names using the attribute spreadsheet.sheet_names. Specifically, you'll be ...

Read the excel files, concat them and append the data − for file in filenames: df = pd.concat (pd.read_excel (file, sheet_name=None), ignore_index=True, sort=False) outputxlsx = outputxlsx.append (df, ...