>>> parser.parse_args(['--version'])

PROG 2.0

* ``'extend'`` - This stores a list, and extends each argument value to the

list.

Example usage::

>>> parser = argparse.ArgumentParser()

>>> parser.add_argument("--foo", action="extend", nargs="+", type=str)

>>> parser.parse_args(["--foo", "f1", "--foo", "f2", "f3", "f4"])

Namespace(foo=['f1', 'f2', 'f3', 'f4'])

You may also specify an arbitrary action by passing an Action subclass or

other object that implements the same interface. The recommended way to do

this is to extend :class:`Action`, overriding the ``__call__`` method

vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])

getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings)

class _ExtendAction(_AppendAction):

def __call__(self, parser, namespace, values, option_string=None):

items = getattr(namespace, self.dest, None)

items = _copy_items(items)

items.extend(values)

setattr(namespace, self.dest, items)

# ==============

# Type classes

self.register('action', 'help', _HelpAction)

self.register('action', 'version', _VersionAction)

self.register('action', 'parsers', _SubParsersAction)

self.register('action', 'extend', _ExtendAction)

# raise an exception if the conflict handler is invalid

self._get_handler()

self.assertEqual(parser.parse_args(['42']), NS(badger='foo[42]'))

class TestActionExtend(ParserTestCase):

argument_signatures = [

Sig('--foo', action="extend", nargs="+", type=str),

]

failures = ()

successes = [

('--foo f1 --foo f2 f3 f4', NS(foo=['f1', 'f2', 'f3', 'f4'])),

]

# ================

# Subparsers tests

# ================

Add an extend action to argparser.