最后，由于冗长，我创建了一个名为www.example.com的简单python文件argparser.py（注意多出的“r”），将其放在python路径中，现在我只使用该路径代替argparse。

'''
Extension to argparse to show default values for arguments and
print out help at proper width on screen.  Basically, it just adds the
MyHelpFormatter to the constructor for the argparse.ArgumentParser
class.

Example usage:
-------------------
import argparser

parser = argparser.ArgumentParser(description="Find and deal with autosave file")
parser.add_argument('-n', '--newer', type=int, default=0, help='how many days back to go, 0->forever')
args = parser.parse_args()
-------------------

Running this with -h would produce:

usage: <progname>.py [-h] [-n NEWER]

Find and deal with autosave file

optional arguments:
  -h, --help            show this help message and exit
  -n NEWER, --newer NEWER
                        how many days back to go, 0->forever (default: 0)

'''

import argparse
import os
import sys

if sys.version_info[0] < 3:
    raise RuntimeError('Need python3 or greater to use argparser.py')

class MyHelpFormatter(argparse.ArgumentDefaultsHelpFormatter):
    columns = -1

    def __init__(self, *args, **kwargs):
        if MyHelpFormatter.columns == -1:
            try:
                MyHelpFormatter.columns = os.get_terminal_size().columns
                if 'width' not in kwargs:
                    kwargs['width'] = MyHelpFormatter.columns
            except OSError:
                # not in a terminal
                pass
        super().__init__(*args, **kwargs)

class ArgumentParser(argparse.ArgumentParser):
    def __init__(self, *args, **kwargs):
        kwargs['formatter_class'] = MyHelpFormatter
        super().__init__(*args, **kwargs)