add_mutually_exclusive_group more than once has incorrectly formatted help.

What steps will reproduce the problem?
1. Create two mutually exclusive groups: eg

agroup = subcmd_parser.add_mutually_exclusive_group()
agroup.add_argument('--a1', action='store_true', help='blah')
agroup.add_argument('--a2', action='store_true', help='blah')
agroup.add_argument('--a3', action='store_true', help='blah')

bgroup = subcmd_parser.add_mutually_exclusive_group()
bgroup.add_argument('--b1', action='store_true', help='blah')
bgroup.add_argument('--b2', action='store_true', help='blah')
bgroup.add_argument('--b3', action='store_true', help='blah')

What is the expected output? What do you see instead?

Expected output (on running a help command which formats help) is:
[ --a1 | --a2 | --a3 ] [ --b1 | --b2 | --b3 ]

You see instead:
[ --a1 | --a2 | --a3 [ --b1 | --b2 | --b3 ]

Note that the closing brace for the first group is missing.

What version of the product are you using? On what operating system?

1.0.1 on Windows.

Please provide any additional information below.

Original issue reported on code.google.com by akla...@gmail.com on 19 Jul 2010 at 8:32

zenlotus / argparse

add_mutually_exclusive_group more than once has incorrectly formatted help. #78