Excel can save a spreadsheet to a CSV file with a few mouse clicks, but if you had to convert hundreds of Excel files to CSVs, it would take hours of clicking. Using the openpyxl module, write a program that reads all the Excel files in the current working directory and outputs them as CSV files.
A single Excel file might contain multiple sheets; you’ll have to create one CSV file per sheet. The filenames of the CSV files should be excel filename>_<sheet title>.csv, where <excel filename> is the filename of the Excel file without the file extension (for example, 'spam_data', not 'spam_data.xlsx') and <sheet title> is the string from the Worksheet object’s title variable.
