parser.parse_known_args() does not work with subparsers

parse_known_args raises an error with subparsers (without subparsers it 
seems okay).  Example script:

import argparse

p = argparse.ArgumentParser()
sub = p.add_subparsers(dest='command')
foo = sub.add_parser('foo')
foo.add_argument('--test')
bar = sub.add_parser('bar')

def parse(*args):
    args = list(args)
    try:
        result = p.parse_known_args(args)
        print args, '->', result
    except SystemExit, e:
        print args, '-exit->', e

parse('foo')
parse('foo', '--test', 'this')
parse('bar')
parse('foo', '--blah')

Original issue reported on code.google.com by ianbick...@gmail.com on 14 Jan 2010 at 11:29

Merged into: #45

zenlotus / argparse

parser.parse_known_args() does not work with subparsers #56