How to save an Excel worksheet as CSV

I want to write a Python script that reads in an Excel spreadsheet and saves some of its worksheets as CSV files.

How can I do this?

I have found third-party modules for reading and writing Excel files from Python, but as far as I can tell, they can only save files in Excel (i.e. *.xls) format. If I'm wrong here, some example code showing how to do what I'm trying to do with these modules would be appreciated.

I also came across one solution that I can't quite understand, but seems to be Windows-specific, and therefore would not help me anyway, since I want to do this in Unix. At any rate, it's not clear to me that this solution can be extended to do what I want to do, even under Windows.

The most basic examples using the two libraries described line by line:

1. Open the xls workbook
2. Reference the first spreadsheet
3. Open in binary write the target csv file
4. Create the default csv writer object
5. Loop over all the rows of the first spreadsheet
6. Dump the rows into the csv

import xlrd
import csv

with xlrd.open_workbook('a_file.xls') as wb:
    sh = wb.sheet_by_index(0)  # or wb.sheet_by_name('name_of_the_sheet_here')
    with open('a_file.csv', 'wb') as f:   # open('a_file.csv', 'w', newline="") for python 3
        c = csv.writer(f)
        for r in range(sh.nrows):
            c.writerow(sh.row_values(r))

import openpyxl
import csv

wb = openpyxl.load_workbook('test.xlsx')
sh = wb.active
with open('test.csv', 'wb') as f:  # open('test.csv', 'w', newline="") for python 3
    c = csv.writer(f)
    for r in sh.rows:
        c.writerow([cell.value for cell in r])