import argparse
import textwrap

def mywrap(text,**kwargs):
    # apply textwrap to each line individually
    text = text.splitlines()
    text = [textwrap.fill(line,**kwargs) for line in text]
    return '\n'.join(text)

description = """\
This description help text will have this first long line wrapped to \
fit the target window size so that your text remains flexible.

    1. But lines such as
    2. this that that are indented beyond the first line's indent,
    3. are reproduced verbatim, with no wrapping.
       or other formatting applied.

You must use backslashes at the end of lines to indicate that you \
want the text to wrap instead of preserving the newline.

It simpler if we avoid the use of leading spaces.
"""

epilog = """Epilog can also be wrapped in a custom way.
    a) point one
    b) point two
rest of the epilog.
"""

arg_help = '''\
This argument's help text will have this first long line wrapped to \
fit the target window size so that your text remains flexible.

    1. But lines such as
    2. this that that are indented beyond the first line's indent,
    3. are reproduced verbatim, with no wrapping.
        or other formatting applied.

You must use backslashes at the end of lines to indicate that you \
want the text to wrap instead of preserving the newline. '''


p = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter,
    description=mywrap(description),
    epilog=mywrap(epilog, width=40))
p.add_argument('--foo', help=mywrap(arg_help, width=50))
p.add_argument('bar', help='positional argument help')
print(p.format_help())

"""
1922:~/mypy/argdev/arggit$ ../python3 wrap_sample.py
usage: wrap_sample.py [-h] [--foo FOO] bar

This description help text will have this first long line wrapped to
fit the target window size so that your text remains flexible.

    1. But lines such as
    2. this that that are indented beyond the first line's indent,
    3. are reproduced verbatim, with no wrapping.
       or other formatting applied.

You must use backslashes at the end of lines to indicate that you want
the text to wrap instead of preserving the newline.

It simpler if we avoid the use of leading spaces.

positional arguments:
  bar         positional argument help

optional arguments:
  -h, --help  show this help message and exit
  --foo FOO   This argument's help text will have this first
              long line wrapped to fit the target window size so
              that your text remains flexible.

                  1. But lines such as
                  2. this that that are indented beyond the
              first line's indent,
                  3. are reproduced verbatim, with no wrapping.
                      or other formatting applied.

              You must use backslashes at the end of lines to
              indicate that you want the text to wrap instead of
              preserving the newline.

Epilog can also be wrapped in a custom
way.
    a) point one
    b) point two
rest of the epilog.

"""