parser = argparse.ArgumentParser(description='some information', usage=
    'use "python %(prog)s --help" for more information', formatter_class=
    argparse.RawTextHelpFormatter)
parser.add_argument('--argument', default=somedefault, type=sometype, help=
    textwrap.dedent(
    """        First line
        Second line
        More lines ... """))
Python argparse: How to insert newline in the help text?