Print default values of CLI arguments in Python

If you would like to print default values of command-line arguments and if you use the argparse.ArgumentParser class in your Python program, consider setting the formatter_class option to argparse.ArgumentDefaultsHelpFormatter.

Example code:

parser = argparse.ArgumentParser(description=sys.modules[__name__]. __doc__ ,
                                 formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('-s', '--std', type=float, default=440.0, help='Standard value')
args = parser.parse_args()