# issue22047 desires a group mechanism that produces
# [ [ -opt1 | -opt2 | -opt3   ] | [ [-opt4] [-opt5] [-opt6] ] ]

# a possible solution with 'UsageGroups' developed for http://bugs.python.org/issue11588

import argparse
parser = argparse.ArgumentParser(prog='PROG',
    formatter_class=argparse.UsageGroupHelpFormatter)
grp1 = parser.add_usage_group(kind='mxg')

grp2 = grp1.add_usage_group(kind='mxg')
grp2.add_argument('--opt1', action='store_true')
grp2.add_argument('--opt2', action='store_true')
grp2.add_argument('--opt3', action='store_true')

grp3 = grp1.add_usage_group(kind='any', joiner=' ', parens='[]')
grp3.add_argument('--opt4', action='store_true')
grp3.add_argument('--opt5', action='store_true')
grp3.add_argument('--opt6', action='store_true')

parser.print_help()

"""
produces:

usage: PROG [-h] [[--opt1 | --opt2 | --opt3] | [--opt4 --opt5 --opt6]]

optional arguments:
  -h, --help  show this help message and exit
  --opt1
  --opt2
  --opt3
  --opt4
  --opt5
  --opt6
"""