old_contents: # 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.
  #
  # Note:
  # - Example Excel files can be downloaded from http://nostarch.com/automatestuff/
  
  import openpyxl, os
  
  for excelFile in os.listdir('.'):
      # Skip non-xlsx files, load the workbook object.
      for sheetName in wb.sheetnames:
          # Loop through every sheet in the workbook.
          sheet = wb['sheetName']
  
          # Create the CSV filename from the Excel filename and sheet title.
          # Create the csv.writer object for this CSV file.
  
          # Loop through every row in the sheet.
          for rowNum in range(1, sheet.max_row + 1):
              rowData = []    # append each cell to this list
              # Loop through each cell in the row.
              for colNum in range(1, sheet.max_column + 1):
                  # Append each cell's data to rowData.
  
              # Write the rowData list to the CSV file.
  
          csvFile.close()
new_contents: # 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.
  #
  # Note:
  # - Example Excel files can be downloaded from http://nostarch.com/automatestuff/
  
  import openpyxl, os, csv
  
  FOLDER_IN = "./excelSpreadsheets"
  FOLDER_OUT = "./csvFiles"
  
  for excelFile in os.listdir(FOLDER_IN):
      # Skip non-xlsx files, load the workbook object.
      if excelFile.endswith(".xlsx"):
          if not FOLDER_IN.endswith('/'):
              excelFilepath = FOLDER_IN + '/' + excelFile
          else:
              excelFilepath = FOLDER_IN + excelFile
          wb = openpyxl.load_workbook(excelFilepath)
      else:
          continue
      for sheetName in wb.sheetnames:
          # Loop through every sheet in the workbook.
          sheet = wb[sheetName]
  
          # Create the CSV filename from the Excel filename and sheet title.
          if not FOLDER_OUT.endswith('/'):
              csvFilepath = FOLDER_OUT + '/' + excelFile[:-5] + '_' + sheet.title + ".csv"
          else:
              csvFilepath = FOLDER_OUT + excelFile[:-5] + '_' + sheet.title + ".csv"
          # Create the csv.writer object for this CSV file.
          csvFile = open(csvFilepath, "w", newline='')
          csvWriter = csv.writer(csvFile)
          # Loop through every row in the sheet.
          for rowNum in range(1, sheet.max_row + 1):
              rowData = []    # append each cell to this list
              # Loop through each cell in the row.
              for colNum in range(1, sheet.max_column + 1):
                  # Append each cell's data to rowData.
                  rowData.append(sheet.cell(row=rowNum, column=colNum).value)
              # Write the rowData list to the CSV file.
              csvWriter.writerow(rowData)
          csvFile.close()
  
subject: Update excelToCSV working solution