why '\n' doesn't work in help option of add_argument?

Question

import argparse

my_parser = argparse.ArgumentParser(description='this is an example')
my_parser.add_argument('-pattern', '--list', nargs='+',
                       help='choose the properties as you need:\n'
                            'including:\n'
                            'power, area, toggle, performance')

pattern = my_parser.parse_args().list
print('example exit')

When I type python help.py -h in terminal, I found that '\n' doesn't work:

D:\py_prj\try>python help.py -h
usage: help.py [-h] [-pattern LIST [LIST ...]]

this is an example

optional arguments:
  -h, --help            show this help message and exit
  -pattern LIST [LIST ...], --list LIST [LIST ...]
                        choose the properties as you need: including: power,      
                        area, toggle, performance

Why?