# Author: Steven J. Bethard <steven.bethard@gmail.com>.

 """Command-line parsing library

 This module is an optparse-inspired command-line parsing library that:

     - handles both optional and positional arguments

     - produces highly informative usage messages

     - supports parsers that dispatch to sub-parsers

 The following is a simple usage example that sums integers from the

 command-line and writes the result to a file::

     parser = argparse.ArgumentParser(

         description='sum the integers at the command line')

     parser.add_argument(

         'integers', metavar='int', nargs='+', type=int,

         help='an integer to be summed')

     parser.add_argument(

         '--log', default=sys.stdout, type=argparse.FileType('w'),

         help='the file where the sum should be written')

     args = parser.parse_args()

     args.log.write('%s' % sum(args.integers))

     args.log.close()

 The module contains the following public classes:

     - ArgumentParser -- The main entry point for command-line parsing. As the

         example above shows, the add_argument() method is used to populate

         the parser with actions for optional and positional arguments. Then

         the parse_args() method is invoked to convert the args at the

         command-line into an object with attributes.

     - ArgumentError -- The exception raised by ArgumentParser objects when

         there are errors with the parser's actions. Errors raised while

         parsing the command-line are caught by ArgumentParser and emitted

         as command-line messages.

     - FileType -- A factory for defining types of files to be created. As the

         example above shows, instances of FileType are typically passed as

         the type= argument of add_argument() calls.

     - Action -- The base class for parser actions. Typically actions are

         selected by passing strings like 'store_true' or 'append_const' to

         the action= argument of add_argument(). However, for greater

         customization of ArgumentParser actions, subclasses of Action may

         be defined and passed as the action= argument.

     - HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,

         ArgumentDefaultsHelpFormatter -- Formatter classes which

         may be passed as the formatter_class= argument to the

         ArgumentParser constructor. HelpFormatter is the default,

         RawDescriptionHelpFormatter and RawTextHelpFormatter tell the parser

         not to change the formatting for help text, and

         ArgumentDefaultsHelpFormatter adds information about argument defaults

         to the help.

 All other classes in this module are considered implementation details.

 (Also note that HelpFormatter and RawDescriptionHelpFormatter are only

 considered public as object names -- the API of the formatter objects is

 still considered an implementation detail.)

 """

 __version__ = '1.1'

 __all__ = [

     'ArgumentParser',

     'ArgumentError',

     'Namespace',

     'Action',

     'FileType',

     'HelpFormatter',

     'RawDescriptionHelpFormatter',

     'RawTextHelpFormatter',

     'ArgumentDefaultsHelpFormatter',

 ]

 import copy as _copy

 import os as _os

 import re as _re

 import sys as _sys

 import textwrap as _textwrap

 from gettext import gettext as _

 def _callable(obj):

     return hasattr(obj, '__call__') or hasattr(obj, '__bases__')

 SUPPRESS = '==SUPPRESS=='

 OPTIONAL = '?'

 ZERO_OR_MORE = '*'

 ONE_OR_MORE = '+'

 PARSER = 'A...'

 REMAINDER = '...'

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

 # Utility functions and classes

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

 class _AttributeHolder(object):

     """Abstract base class that provides __repr__.

     The __repr__ method returns a string in the format::

         ClassName(attr=name, attr=name, ...)

     The attributes are determined either by a class-level attribute,

     '_kwarg_names', or by inspecting the instance __dict__.

     """

     def __repr__(self):

         type_name = type(self).__name__

         arg_strings = []

         for arg in self._get_args():

             arg_strings.append(repr(arg))

         for name, value in self._get_kwargs():

             arg_strings.append('%s=%r' % (name, value))

         return '%s(%s)' % (type_name, ', '.join(arg_strings))

     def _get_kwargs(self):

         return sorted(self.__dict__.items())

     def _get_args(self):

         return []

 def _ensure_value(namespace, name, value):

     if getattr(namespace, name, None) is None:

         setattr(namespace, name, value)

     return getattr(namespace, name)

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

 # Formatting Help

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

 class HelpFormatter(object):

     """Formatter for generating usage messages and argument help strings.

     Only the name of this class is considered a public API. All the methods

     provided by the class are considered an implementation detail.

     """

     def __init__(self,

                  prog,

                  indent_increment=2,

                  max_help_position=24,

                  width=None):

         # default setting for width

         if width is None:

             try:

                 width = int(_os.environ['COLUMNS'])

             except (KeyError, ValueError):

                 width = 80

             width -= 2

         self._prog = prog

         self._indent_increment = indent_increment

         self._max_help_position = max_help_position

         self._width = width

         self._current_indent = 0

         self._level = 0

         self._action_max_length = 0

         self._root_section = self._Section(self, None)

         self._current_section = self._root_section

         self._whitespace_matcher = _re.compile(r'\s+')

         self._long_break_matcher = _re.compile(r'\n\n\n+')

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

     # Section and indentation methods

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

     def _indent(self):

         self._current_indent += self._indent_increment

         self._level += 1

     def _dedent(self):

         self._current_indent -= self._indent_increment

         assert self._current_indent >= 0, 'Indent decreased below 0.'

         self._level -= 1

     class _Section(object):

         def __init__(self, formatter, parent, heading=None):

             self.formatter = formatter

             self.parent = parent

             self.heading = heading

             self.items = []

         def format_help(self):

             # format the indented section

             if self.parent is not None:

                 self.formatter._indent()

             join = self.formatter._join_parts

             for func, args in self.items:

                 func(*args)

             item_help = join([func(*args) for func, args in self.items])

             if self.parent is not None:

                 self.formatter._dedent()

             # return nothing if the section was empty

             if not item_help:

                 return ''

             # add the heading if the section was non-empty

             if self.heading is not SUPPRESS and self.heading is not None:

                 current_indent = self.formatter._current_indent

                 heading = '%*s%s:\n' % (current_indent, '', self.heading)

             else:

                 heading = ''

             # join the section-initial newline, the heading and the help

             return join(['\n', heading, item_help, '\n'])

     def _add_item(self, func, args):

         self._current_section.items.append((func, args))

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

     # Message building methods

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

     def start_section(self, heading):

         self._indent()

         section = self._Section(self, self._current_section, heading)

         self._add_item(section.format_help, [])

         self._current_section = section

     def end_section(self):

         self._current_section = self._current_section.parent

         self._dedent()

     def add_text(self, text):

         if text is not SUPPRESS and text is not None:

             self._add_item(self._format_text, [text])

     def add_usage(self, usage, actions, groups, prefix=None):

         if usage is not SUPPRESS:

             args = usage, actions, groups, prefix

             self._add_item(self._format_usage, args)

     def add_argument(self, action):

         if action.help is not SUPPRESS:

             # find all invocations

             get_invocation = self._format_action_invocation

             invocations = [get_invocation(action)]

             for subaction in self._iter_indented_subactions(action):

                 invocations.append(get_invocation(subaction))

             # update the maximum item length

             invocation_length = max([len(s) for s in invocations])

             action_length = invocation_length + self._current_indent

             self._action_max_length = max(self._action_max_length,

                                           action_length)

             # add the item to the list

             self._add_item(self._format_action, [action])

     def add_arguments(self, actions):

         for action in actions:

             self.add_argument(action)

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

     # Help-formatting methods

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

     def format_help(self):

         help = self._root_section.format_help()

         if help:

             help = self._long_break_matcher.sub('\n\n', help)

             help = help.strip('\n') + '\n'

         return help

     def _join_parts(self, part_strings):

         return ''.join([part

                         for part in part_strings

                         if part and part is not SUPPRESS])

     def _format_usage(self, usage, actions, groups, prefix):

         if prefix is None:

             prefix = _('usage: ')

         # if usage is specified, use that

         if usage is not None:

             usage = usage % dict(prog=self._prog)

         # if no optionals or positionals are available, usage is just prog

         elif usage is None and not actions:

             usage = '%(prog)s' % dict(prog=self._prog)

         # if optionals and positionals are available, calculate usage

         elif usage is None:

             prog = '%(prog)s' % dict(prog=self._prog)

             # split optionals from positionals

             optionals = []

             positionals = []

             for action in actions:

                 if action.option_strings:

                     optionals.append(action)

                 else:

                     positionals.append(action)

             # build full usage string

             format = self._format_actions_usage

             action_usage = format(optionals + positionals, groups)

             usage = ' '.join([s for s in [prog, action_usage] if s])

             # wrap the usage parts if it's too long

             text_width = self._width - self._current_indent

             if len(prefix) + len(usage) > text_width:

                 # break usage into wrappable parts

                 part_regexp = r'\(.*?\)+|\[.*?\]+|\S+'

                 opt_usage = format(optionals, groups)

                 pos_usage = format(positionals, groups)

                 opt_parts = _re.findall(part_regexp, opt_usage)

                 pos_parts = _re.findall(part_regexp, pos_usage)

                 assert ' '.join(opt_parts) == opt_usage

                 assert ' '.join(pos_parts) == pos_usage

                 # helper for wrapping lines

                 def get_lines(parts, indent, prefix=None):

                     lines = []

                     line = []

                     if prefix is not None:

                         line_len = len(prefix) - 1

                     else:

                         line_len = len(indent) - 1

                     for part in parts:

                         if line_len + 1 + len(part) > text_width:

                             lines.append(indent + ' '.join(line))

                             line = []

                             line_len = len(indent) - 1

                         line.append(part)

                         line_len += len(part) + 1

                     if line:

                         lines.append(indent + ' '.join(line))

                     if prefix is not None:

                         lines[0] = lines[0][len(indent):]

                     return lines

                 # if prog is short, follow it with optionals or positionals

                 if len(prefix) + len(prog) <= 0.75 * text_width:

                     indent = ' ' * (len(prefix) + len(prog) + 1)

                     if opt_parts:

                         lines = get_lines([prog] + opt_parts, indent, prefix)

                         lines.extend(get_lines(pos_parts, indent))

                     elif pos_parts:

                         lines = get_lines([prog] + pos_parts, indent, prefix)

                     else:

                         lines = [prog]

                 # if prog is long, put it on its own line

                 else:

                     indent = ' ' * len(prefix)

                     parts = opt_parts + pos_parts

                     lines = get_lines(parts, indent)

                     if len(lines) > 1:

                         lines = []

                         lines.extend(get_lines(opt_parts, indent))

                         lines.extend(get_lines(pos_parts, indent))

                     lines = [prog] + lines

                 # join lines into usage

                 usage = '\n'.join(lines)

         # prefix with 'usage:'

         return '%s%s\n\n' % (prefix, usage)

     def _format_actions_usage(self, actions, groups):

         # find group indices and identify actions in groups

         group_actions = set()

         inserts = {}

         for group in groups:

             try:

                 start = actions.index(group._group_actions[0])

             except ValueError:

                 continue

             else:

                 end = start + len(group._group_actions)

                 if actions[start:end] == group._group_actions:

                     for action in group._group_actions:

                         group_actions.add(action)

                     if not group.required:

                         inserts[start] = '['

                         inserts[end] = ']'

                     else:

                         inserts[start] = '('

                         inserts[end] = ')'

                     for i in range(start + 1, end):

                         inserts[i] = '|'

         # collect all actions format strings

         parts = []

         for i, action in enumerate(actions):

             # suppressed arguments are marked with None

             # remove | separators for suppressed arguments

             if action.help is SUPPRESS:

                 parts.append(None)

                 if inserts.get(i) == '|':

                     inserts.pop(i)

                 elif inserts.get(i + 1) == '|':

                     inserts.pop(i + 1)

             # produce all arg strings

             elif not action.option_strings:

                 part = self._format_args(action, action.dest)

                 # if it's in a group, strip the outer []

                 if action in group_actions:

                     if part[0] == '[' and part[-1] == ']':

                         part = part[1:-1]

                 # add the action string to the list

                 parts.append(part)

             # produce the first way to invoke the option in brackets

             else:

                 option_string = action.option_strings[0]

                 # if the Optional doesn't take a value, format is:

                 #    -s or --long

                 if action.nargs == 0:

                     part = '%s' % option_string

                 # if the Optional takes a value, format is:

                 #    -s ARGS or --long ARGS

                 else:

                     default = action.dest.upper()

                     args_string = self._format_args(action, default)

                     part = '%s %s' % (option_string, args_string)

                 # make it look optional if it's not required or in a group

                 if not action.required and action not in group_actions:

                     part = '[%s]' % part

                 # add the action string to the list

                 parts.append(part)

         # insert things at the necessary indices

         for i in sorted(inserts, reverse=True):

             parts[i:i] = [inserts[i]]

         # join all the action items with spaces

         text = ' '.join([item for item in parts if item is not None])

         # clean up separators for mutually exclusive groups

         open = r'[\[(]'

         close = r'[\])]'

         text = _re.sub(r'(%s) ' % open, r'\1', text)

         text = _re.sub(r' (%s)' % close, r'\1', text)

         text = _re.sub(r'%s *%s' % (open, close), r'', text)

         text = _re.sub(r'\(([^|]*)\)', r'\1', text)

         text = text.strip()

         # return the text

         return text

     def _format_text(self, text):

         if '%(prog)' in text:

             text = text % dict(prog=self._prog)

         text_width = self._width - self._current_indent

         indent = ' ' * self._current_indent

         return self._fill_text(text, text_width, indent) + '\n\n'

     def _format_action(self, action):

         # determine the required width and the entry label

         help_position = min(self._action_max_length + 2,

                             self._max_help_position)

         help_width = self._width - help_position

         action_width = help_position - self._current_indent - 2

         action_header = self._format_action_invocation(action)

         # ho nelp; start on same line and add a final newline

         if not action.help:

             tup = self._current_indent, '', action_header

             action_header = '%*s%s\n' % tup

         # short action name; start on the same line and pad two spaces

         elif len(action_header) <= action_width:

             tup = self._current_indent, '', action_width, action_header

             action_header = '%*s%-*s  ' % tup

             indent_first = 0

         # long action name; start on the next line

         else:

             tup = self._current_indent, '', action_header

             action_header = '%*s%s\n' % tup

             indent_first = help_position

         # collect the pieces of the action help

         parts = [action_header]

         # if there was help for the action, add lines of help text

         if action.help:

             help_text = self._expand_help(action)

             help_lines = self._split_lines(help_text, help_width)

             parts.append('%*s%s\n' % (indent_first, '', help_lines[0]))

             for line in help_lines[1:]:

                 parts.append('%*s%s\n' % (help_position, '', line))

         # or add a newline if the description doesn't end with one

         elif not action_header.endswith('\n'):

             parts.append('\n')

         # if there are any sub-actions, add their help as well

         for subaction in self._iter_indented_subactions(action):

             parts.append(self._format_action(subaction))

         # return a single string

         return self._join_parts(parts)

     def _format_action_invocation(self, action):

         if not action.option_strings:

             metavar, = self._metavar_formatter(action, action.dest)(1)

             return metavar

         else:

             parts = []

             # if the Optional doesn't take a value, format is:

             #    -s, --long

             if action.nargs == 0:

                 parts.extend(action.option_strings)

             # if the Optional takes a value, format is:

             #    -s ARGS, --long ARGS

             else:

                 default = action.dest.upper()

                 args_string = self._format_args(action, default)

                 for option_string in action.option_strings:

                     parts.append('%s %s' % (option_string, args_string))

             return ', '.join(parts)

     def _metavar_formatter(self, action, default_metavar):

         if action.metavar is not None:

             result = action.metavar

         elif action.choices is not None:

             choice_strs = [str(choice) for choice in action.choices]

             result = '{%s}' % ','.join(choice_strs)

         else:

             result = default_metavar

         def format(tuple_size):

             if isinstance(result, tuple):

                 return result

             else:

                 return (result, ) * tuple_size

         return format

     def _format_args(self, action, default_metavar):

         get_metavar = self._metavar_formatter(action, default_metavar)

         if action.nargs is None:

             result = '%s' % get_metavar(1)

         elif action.nargs == OPTIONAL:

             result = '[%s]' % get_metavar(1)

         elif action.nargs == ZERO_OR_MORE:

             result = '[%s [%s ...]]' % get_metavar(2)

         elif action.nargs == ONE_OR_MORE:

             result = '%s [%s ...]' % get_metavar(2)

         elif action.nargs == REMAINDER:

             result = '...'

         elif action.nargs == PARSER:

             result = '%s ...' % get_metavar(1)

         else:

             formats = ['%s' for _ in range(action.nargs)]

             result = ' '.join(formats) % get_metavar(action.nargs)

         return result

     def _expand_help(self, action):

         params = dict(vars(action), prog=self._prog)

         for name in list(params):

             if params[name] is SUPPRESS:

                 del params[name]

         for name in list(params):

             if hasattr(params[name], '__name__'):

                 params[name] = params[name].__name__

         if params.get('choices') is not None:

             choices_str = ', '.join([str(c) for c in params['choices']])

             params['choices'] = choices_str

         return self._get_help_string(action) % params

     def _iter_indented_subactions(self, action):

         try:

             get_subactions = action._get_subactions

         except AttributeError:

             pass

         else:

             self._indent()

             for subaction in get_subactions():

                 yield subaction

             self._dedent()

     def _split_lines(self, text, width):

         text = self._whitespace_matcher.sub(' ', text).strip()

         return _textwrap.wrap(text, width)

     def _fill_text(self, text, width, indent):

         text = self._whitespace_matcher.sub(' ', text).strip()

         return _textwrap.fill(text, width, initial_indent=indent,

                                            subsequent_indent=indent)

     def _get_help_string(self, action):

         return action.help

 class RawDescriptionHelpFormatter(HelpFormatter):

     """Help message formatter which retains any formatting in descriptions.

     Only the name of this class is considered a public API. All the methods

     provided by the class are considered an implementation detail.

     """

     def _fill_text(self, text, width, indent):

         return ''.join([indent + line for line in text.splitlines(True)])

 class RawTextHelpFormatter(RawDescriptionHelpFormatter):

     """Help message formatter which retains formatting of all help text.

     Only the name of this class is considered a public API. All the methods

     provided by the class are considered an implementation detail.

     """

     def _split_lines(self, text, width):

         return text.splitlines()

 class ArgumentDefaultsHelpFormatter(HelpFormatter):

     """Help message formatter which adds default values to argument help.

     Only the name of this class is considered a public API. All the methods

     provided by the class are considered an implementation detail.

     """

     def _get_help_string(self, action):

         help = action.help

         if '%(default)' not in action.help:

             if action.default is not SUPPRESS:

                 defaulting_nargs = [OPTIONAL, ZERO_OR_MORE]

                 if action.option_strings or action.nargs in defaulting_nargs:

                     help += ' (default: %(default)s)'

         return help

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

 # Options and Arguments

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

 def _get_action_name(argument):

     if argument is None:

         return None

     elif argument.option_strings:

         return  '/'.join(argument.option_strings)

     elif argument.metavar not in (None, SUPPRESS):

         return argument.metavar

     elif argument.dest not in (None, SUPPRESS):

         return argument.dest

     else:

         return None

 class ArgumentError(Exception):

     """An error from creating or using an argument (optional or positional).

     The string value of this exception is the message, augmented with

     information about the argument that caused it.

     """

     def __init__(self, argument, message):

         self.argument_name = _get_action_name(argument)

         self.message = message

     def __str__(self):

         if self.argument_name is None:

             format = '%(message)s'

         else:

             format = 'argument %(argument_name)s: %(message)s'

         return format % dict(message=self.message,

                              argument_name=self.argument_name)

 class ArgumentTypeError(Exception):

     """An error from trying to convert a command line string to a type."""

     pass

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

 # Action classes

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

 class Action(_AttributeHolder):

     """Information about how to convert command line strings to Python objects.

     Action objects are used by an ArgumentParser to represent the information

     needed to parse a single argument from one or more strings from the

     command line. The keyword arguments to the Action constructor are also

     all attributes of Action instances.

     Keyword Arguments:

         - option_strings -- A list of command-line option strings which

             should be associated with this action.

         - dest -- The name of the attribute to hold the created object(s)

         - nargs -- The number of command-line arguments that should be

             consumed. By default, one argument will be consumed and a single

             value will be produced.  Other values include:

                 - N (an integer) consumes N arguments (and produces a list)

                 - '?' consumes zero or one arguments

                 - '*' consumes zero or more arguments (and produces a list)

                 - '+' consumes one or more arguments (and produces a list)

             Note that the difference between the default and nargs=1 is that

             with the default, a single value will be produced, while with

             nargs=1, a list containing a single value will be produced.

         - const -- The value to be produced if the option is specified and the

             option uses an action that takes no values.

         - default -- The value to be produced if the option is not specified.

         - type -- The type which the command-line arguments should be converted

             to, should be one of 'string', 'int', 'float', 'complex' or a

             callable object that accepts a single string argument. If None,

             'string' is assumed.

         - choices -- A container of values that should be allowed. If not None,

             after a command-line argument has been converted to the appropriate

             type, an exception will be raised if it is not a member of this

             collection.

         - required -- True if the action must always be specified at the

             command line. This is only meaningful for optional command-line

             arguments.

         - help -- The help string describing the argument.

         - metavar -- The name to be used for the option's argument with the

             help string. If None, the 'dest' value will be used as the name.

     """

     def __init__(self,

                  option_strings,

                  dest,

                  nargs=None,

                  const=None,

                  default=None,

                  type=None,

                  choices=None,

                  required=False,

                  help=None,

                  metavar=None):

         self.option_strings = option_strings

         self.dest = dest

         self.nargs = nargs

         self.const = const

         self.default = default

         self.type = type

         self.choices = choices

         self.required = required

         self.help = help

         self.metavar = metavar

     def _get_kwargs(self):

         names = [

             'option_strings',

             'dest',

             'nargs',

             'const',

             'default',

             'type',

             'choices',

             'help',

             'metavar',

         ]

         return [(name, getattr(self, name)) for name in names]

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

         raise NotImplementedError(_('.__call__() not defined'))

 class _StoreAction(Action):

     def __init__(self,

                  option_strings,

                  dest,

                  nargs=None,

                  const=None,

                  default=None,

                  type=None,

                  choices=None,

                  required=False,

                  help=None,

                  metavar=None):

         if nargs == 0:

             raise ValueError('nargs for store actions must be > 0; if you '

                              'have nothing to store, actions such as store '

                              'true or store const may be more appropriate')

         if const is not None and nargs != OPTIONAL:

             raise ValueError('nargs must be %r to supply const' % OPTIONAL)

         super(_StoreAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=nargs,

             const=const,

             default=default,

             type=type,

             choices=choices,

             required=required,

             help=help,

             metavar=metavar)

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

         setattr(namespace, self.dest, values)

 class _StoreConstAction(Action):

     def __init__(self,

                  option_strings,

                  dest,

                  const,

                  default=None,

                  required=False,

                  help=None,

                  metavar=None):

         super(_StoreConstAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=0,

             const=const,

             default=default,

             required=required,

             help=help)

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

         setattr(namespace, self.dest, self.const)

 class _StoreTrueAction(_StoreConstAction):

     def __init__(self,

                  option_strings,

                  dest,

                  default=False,

                  required=False,

                  help=None):

         super(_StoreTrueAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             const=True,

             default=default,

             required=required,

             help=help)

 class _StoreFalseAction(_StoreConstAction):

     def __init__(self,

                  option_strings,

                  dest,

                  default=True,

                  required=False,

                  help=None):

         super(_StoreFalseAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             const=False,

             default=default,

             required=required,

             help=help)

 class _AppendAction(Action):

     def __init__(self,

                  option_strings,

                  dest,

                  nargs=None,

                  const=None,

                  default=None,

                  type=None,

                  choices=None,

                  required=False,

                  help=None,

                  metavar=None):

         if nargs == 0:

             raise ValueError('nargs for append actions must be > 0; if arg '

                              'strings are not supplying the value to append, '

                              'the append const action may be more appropriate')

         if const is not None and nargs != OPTIONAL:

             raise ValueError('nargs must be %r to supply const' % OPTIONAL)

         super(_AppendAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=nargs,

             const=const,

             default=default,

             type=type,

             choices=choices,

             required=required,

             help=help,

             metavar=metavar)

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

         items = _copy.copy(_ensure_value(namespace, self.dest, []))

         items.append(values)

         setattr(namespace, self.dest, items)

 class _AppendConstAction(Action):

     def __init__(self,

                  option_strings,

                  dest,

                  const,

                  default=None,

                  required=False,

                  help=None,

                  metavar=None):

         super(_AppendConstAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=0,

             const=const,

             default=default,

             required=required,

             help=help,

             metavar=metavar)

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

         items = _copy.copy(_ensure_value(namespace, self.dest, []))

         items.append(self.const)

         setattr(namespace, self.dest, items)

 class _CountAction(Action):

     def __init__(self,

                  option_strings,

                  dest,

                  default=None,

                  required=False,

                  help=None):

         super(_CountAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=0,

             default=default,

             required=required,

             help=help)

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

         new_count = _ensure_value(namespace, self.dest, 0) + 1

         setattr(namespace, self.dest, new_count)

 class _HelpAction(Action):

     def __init__(self,

                  option_strings,

                  dest=SUPPRESS,

                  default=SUPPRESS,

                  help=None):

         super(_HelpAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             default=default,

             nargs=0,

             help=help)

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

         parser.print_help()

         parser.exit()

 class _VersionAction(Action):

     def __init__(self,

                  option_strings,

                  version=None,

                  dest=SUPPRESS,

                  default=SUPPRESS,

                  help="show program's version number and exit"):

         super(_VersionAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             default=default,

             nargs=0,

             help=help)

         self.version = version

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

         version = self.version

         if version is None:

             version = parser.version

         formatter = parser._get_formatter()

         formatter.add_text(version)

         parser.exit(message=formatter.format_help())

 class _SubParsersAction(Action):

     class _ChoicesPseudoAction(Action):

         def __init__(self, name, help):

             sup = super(_SubParsersAction._ChoicesPseudoAction, self)

             sup.__init__(option_strings=[], dest=name, help=help)

     def __init__(self,

                  option_strings,

                  prog,

                  parser_class,

                  dest=SUPPRESS,

                  help=None,

                  metavar=None):

         self._prog_prefix = prog

         self._parser_class = parser_class

         self._name_parser_map = {}

         self._choices_actions = []

         super(_SubParsersAction, self).__init__(

             option_strings=option_strings,

             dest=dest,

             nargs=PARSER,

             choices=self._name_parser_map,

             help=help,

             metavar=metavar)

     def add_parser(self, name, **kwargs):

         # set prog from the existing prefix

         if kwargs.get('prog') is None:

             kwargs['prog'] = '%s %s' % (self._prog_prefix, name)

         # create a pseudo-action to hold the choice help

         if 'help' in kwargs:

             help = kwargs.pop('help')

             choice_action = self._ChoicesPseudoAction(name, help)

             self._choices_actions.append(choice_action)

         # create the parser and add it to the map

         parser = self._parser_class(**kwargs)

         self._name_parser_map[name] = parser

         return parser

     def _get_subactions(self):

         return self._choices_actions

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

         parser_name = values[0]

         arg_strings = values[1:]

         # set the parser name if requested

         if self.dest is not SUPPRESS:

             setattr(namespace, self.dest, parser_name)

         # select the parser

         try:

             parser = self._name_parser_map[parser_name]

         except KeyError:

             tup = parser_name, ', '.join(self._name_parser_map)

             msg = _('unknown parser %r (choices: %s)' % tup)

             raise ArgumentError(self, msg)

         # parse all the remaining options into the namespace

         parser.parse_args(arg_strings, namespace)

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

 # Type classes

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

 class FileType(object):

     """Factory for creating file object types

     Instances of FileType are typically passed as type= arguments to the

     ArgumentParser add_argument() method.

     Keyword Arguments:

         - mode -- A string indicating how the file is to be opened. Accepts the

             same values as the builtin open() function.

         - bufsize -- The file's desired buffer size. Accepts the same values as

             the builtin open() function.

     """

     def __init__(self, mode='r', bufsize=None):

         self._mode = mode

         self._bufsize = bufsize

     def __call__(self, string):

         # the special argument "-" means sys.std{in,out}

         if string == '-':

             if 'r' in self._mode:

                 return _sys.stdin

             elif 'w' in self._mode:

                 return _sys.stdout

             else:

                 msg = _('argument "-" with mode %r' % self._mode)

                 raise ValueError(msg)

         # all other arguments are used as file names

         if self._bufsize:

             return open(string, self._mode, self._bufsize)

         else:

             return open(string, self._mode)

     def __repr__(self):

         args = [self._mode, self._bufsize]

         args_str = ', '.join([repr(arg) for arg in args if arg is not None])

         return '%s(%s)' % (type(self).__name__, args_str)

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

 # Optional and Positional Parsing

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

 class Namespace(_AttributeHolder):

     """Simple object for storing attributes.

     Implements equality by attribute names and values, and provides a simple

     string representation.

     """

     def __init__(self, **kwargs):

         for name in kwargs:

             setattr(self, name, kwargs[name])

     def __eq__(self, other):

         return vars(self) == vars(other)

     def __ne__(self, other):

         return not (self == other)

     def __contains__(self, key):

         return key in self.__dict__

 class _ActionsContainer(object):

     def __init__(self,

                  description,

                  prefix_chars,

                  argument_default,

                  conflict_handler):

         super(_ActionsContainer, self).__init__()

         self.description = description

         self.argument_default = argument_default

         self.prefix_chars = prefix_chars

         self.conflict_handler = conflict_handler

         # set up registries

         self._registries = {}

         # register actions

         self.register('action', None, _StoreAction)

         self.register('action', 'store', _StoreAction)

         self.register('action', 'store_const', _StoreConstAction)

         self.register('action', 'store_true', _StoreTrueAction)

         self.register('action', 'store_false', _StoreFalseAction)

         self.register('action', 'append', _AppendAction)

         self.register('action', 'append_const', _AppendConstAction)

         self.register('action', 'count', _CountAction)

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

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

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

         # raise an exception if the conflict handler is invalid

         self._get_handler()

         # action storage

         self._actions = []

         self._option_string_actions = {}

         # groups

         self._action_groups = []

         self._mutually_exclusive_groups = []

         # defaults storage

         self._defaults = {}

         # determines whether an "option" looks like a negative number

         self._negative_number_matcher = _re.compile(r'^-\d+$|^-\d*\.\d+$')

         # whether or not there are any optionals that look like negative

         # numbers -- uses a list so it can be shared and edited

         self._has_negative_number_optionals = []

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

     # Registration methods

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

     def register(self, registry_name, value, object):

         registry = self._registries.setdefault(registry_name, {})

         registry[value] = object

     def _registry_get(self, registry_name, value, default=None):

         return self._registries[registry_name].get(value, default)

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

     # Namespace default accessor methods

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

     def set_defaults(self, **kwargs):

         self._defaults.update(kwargs)

         # if these defaults match any existing arguments, replace

         # the previous default on the object with the new one

         for action in self._actions:

             if action.dest in kwargs:

                 action.default = kwargs[action.dest]

     def get_default(self, dest):

         for action in self._actions:

             if action.dest == dest and action.default is not None:

                 return action.default

         return self._defaults.get(dest, None)

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

     # Adding argument actions

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

     def add_argument(self, *args, **kwargs):

         """

         add_argument(dest, ..., name=value, ...)

         add_argument(option_string, option_string, ..., name=value, ...)

         """

         # if no positional args are supplied or only one is supplied and

         # it doesn't look like an option string, parse a positional

         # argument

         chars = self.prefix_chars

         if not args or len(args) == 1 and args[0][0] not in chars:

             if args and 'dest' in kwargs:

                 raise ValueError('dest supplied twice for positional argument')

             kwargs = self._get_positional_kwargs(*args, **kwargs)

         # otherwise, we're adding an optional argument

         else:

             kwargs = self._get_optional_kwargs(*args, **kwargs)

         # if no default was supplied, use the parser-level default

         if 'default' not in kwargs:

             dest = kwargs['dest']

             if dest in self._defaults:

                 kwargs['default'] = self._defaults[dest]

             elif self.argument_default is not None:

                 kwargs['default'] = self.argument_default

         # create the action object, and add it to the parser

         action_class = self._pop_action_class(kwargs)

         if not _callable(action_class):

             raise ValueError('unknown action "%s"' % action_class)

         action = action_class(**kwargs)

         # raise an error if the action type is not callable

         type_func = self._registry_get('type', action.type, action.type)

         if not _callable(type_func):

             raise ValueError('%r is not callable' % type_func)

         return self._add_action(action)

     def add_argument_group(self, *args, **kwargs):

         group = _ArgumentGroup(self, *args, **kwargs)

         self._action_groups.append(group)

         return group

     def add_mutually_exclusive_group(self, **kwargs):

         group = _MutuallyExclusiveGroup(self, **kwargs)

         self._mutually_exclusive_groups.append(group)

         return group

     def _add_action(self, action):

         # resolve any conflicts

         self._check_conflict(action)

         # add to actions list

         self._actions.append(action)

         action.container = self

         # index the action by any option strings it has

         for option_string in action.option_strings:

             self._option_string_actions[option_string] = action

         # set the flag if any option strings look like negative numbers

         for option_string in action.option_strings:

             if self._negative_number_matcher.match(option_string):

                 if not self._has_negative_number_optionals:

                     self._has_negative_number_optionals.append(True)

         # return the created action

         return action

     def _remove_action(self, action):

         self._actions.remove(action)

     def _add_container_actions(self, container):

         # collect groups by titles

         title_group_map = {}

         for group in self._action_groups:

             if group.title in title_group_map:

                 msg = _('cannot merge actions - two groups are named %r')

                 raise ValueError(msg % (group.title))

             title_group_map[group.title] = group

         # map each action to its group

         group_map = {}

         for group in container._action_groups:

             # if a group with the title exists, use that, otherwise

             # create a new group matching the container's group

             if group.title not in title_group_map:

                 title_group_map[group.title] = self.add_argument_group(

                     title=group.title,

                     description=group.description,

                     conflict_handler=group.conflict_handler)

             # map the actions to their new group

             for action in group._group_actions:

                 group_map[action] = title_group_map[group.title]

         # add container's mutually exclusive groups

         # NOTE: if add_mutually_exclusive_group ever gains title= and

         # description= then this code will need to be expanded as above

         for group in container._mutually_exclusive_groups:

             mutex_group = self.add_mutually_exclusive_group(

                 required=group.required)

             # map the actions to their new mutex group

             for action in group._group_actions:

                 group_map[action] = mutex_group

         # add all actions to this container or their group

         for action in container._actions:

             group_map.get(action, self)._add_action(action)

     def _get_positional_kwargs(self, dest, **kwargs):

         # make sure required is not specified

         if 'required' in kwargs:

             msg = _("'required' is an invalid argument for positionals")

             raise TypeError(msg)

         # mark positional arguments as required if at least one is

         # always required

         if kwargs.get('nargs') not in [OPTIONAL, ZERO_OR_MORE]:

             kwargs['required'] = True

         if kwargs.get('nargs') == ZERO_OR_MORE and 'default' not in kwargs:

             kwargs['required'] = True

         # return the keyword arguments with no option strings

         return dict(kwargs, dest=dest, option_strings=[])

     def _get_optional_kwargs(self, *args, **kwargs):

         # determine short and long option strings

         option_strings = []

         long_option_strings = []

         for option_string in args:

             # error on strings that don't start with an appropriate prefix

             if not option_string[0] in self.prefix_chars:

                 msg = _('invalid option string %r: '

                         'must start with a character %r')

                 tup = option_string, self.prefix_chars

                 raise ValueError(msg % tup)

             # strings starting with two prefix characters are long options

             option_strings.append(option_string)

             if option_string[0] in self.prefix_chars:

                 if len(option_string) > 1:

                     if option_string[1] in self.prefix_chars:

                         long_option_strings.append(option_string)

         # infer destination, '--foo-bar' -> 'foo_bar' and '-x' -> 'x'

         dest = kwargs.pop('dest', None)

         if dest is None:

             if long_option_strings:

                 dest_option_string = long_option_strings[0]

             else:

                 dest_option_string = option_strings[0]

             dest = dest_option_string.lstrip(self.prefix_chars)

             if not dest:

                 msg = _('dest= is required for options like %r')

                 raise ValueError(msg % option_string)

             dest = dest.replace('-', '_')

         # return the updated keyword arguments

         return dict(kwargs, dest=dest, option_strings=option_strings)

     def _pop_action_class(self, kwargs, default=None):

         action = kwargs.pop('action', default)

         return self._registry_get('action', action, action)

     def _get_handler(self):

         # determine function from conflict handler string

         handler_func_name = '_handle_conflict_%s' % self.conflict_handler

         try:

             return getattr(self, handler_func_name)

         except AttributeError:

             msg = _('invalid conflict_resolution value: %r')

             raise ValueError(msg % self.conflict_handler)

     def _check_conflict(self, action):

         # find all options that conflict with this option

         confl_optionals = []

         for option_string in action.option_strings:

             if option_string in self._option_string_actions:

                 confl_optional = self._option_string_actions[option_string]

                 confl_optionals.append((option_string, confl_optional))

         # resolve any conflicts

         if confl_optionals:

             conflict_handler = self._get_handler()

             conflict_handler(action, confl_optionals)

     def _handle_conflict_error(self, action, conflicting_actions):

         message = _('conflicting option string(s): %s')

         conflict_string = ', '.join([option_string

                                      for option_string, action

                                      in conflicting_actions])

         raise ArgumentError(action, message % conflict_string)

     def _handle_conflict_resolve(self, action, conflicting_actions):

         # remove all conflicting options

         for option_string, action in conflicting_actions:

             # remove the conflicting option

             action.option_strings.remove(option_string)

             self._option_string_actions.pop(option_string, None)

             # if the option now has no option string, remove it from the

             # container holding it

             if not action.option_strings:

                 action.container._remove_action(action)

 class _ArgumentGroup(_ActionsContainer):

     def __init__(self, container, title=None, description=None, **kwargs):

         # add any missing keyword arguments by checking the container

         update = kwargs.setdefault

         update('conflict_handler', container.conflict_handler)

         update('prefix_chars', container.prefix_chars)

         update('argument_default', container.argument_default)

         super_init = super(_ArgumentGroup, self).__init__

         super_init(description=description, **kwargs)

         # group attributes

         self.title = title

         self._group_actions = []

         # share most attributes with the container

         self._registries = container._registries

         self._actions = container._actions

         self._option_string_actions = container._option_string_actions

         self._defaults = container._defaults

         self._has_negative_number_optionals = \

             container._has_negative_number_optionals

     def _add_action(self, action):

         action = super(_ArgumentGroup, self)._add_action(action)

         self._group_actions.append(action)

         return action

     def _remove_action(self, action):

         super(_ArgumentGroup, self)._remove_action(action)

         self._group_actions.remove(action)

 class _MutuallyExclusiveGroup(_ArgumentGroup):

     def __init__(self, container, required=False):

         super(_MutuallyExclusiveGroup, self).__init__(container)

         self.required = required

         self._container = container

     def _add_action(self, action):

         if action.required:

             msg = _('mutually exclusive arguments must be optional')

             raise ValueError(msg)

         action = self._container._add_action(action)

         self._group_actions.append(action)

         return action

     def _remove_action(self, action):

         self._container._remove_action(action)

         self._group_actions.remove(action)

 class ArgumentParser(_AttributeHolder, _ActionsContainer):

     """Object for parsing command line strings into Python objects.

     Keyword Arguments:

         - prog -- The name of the program (default: sys.argv[0])

         - usage -- A usage message (default: auto-generated from arguments)

         - description -- A description of what the program does

         - epilog -- Text following the argument descriptions

         - parents -- Parsers whose arguments should be copied into this one

         - formatter_class -- HelpFormatter class for printing help messages

         - prefix_chars -- Characters that prefix optional arguments

         - fromfile_prefix_chars -- Characters that prefix files containing

             additional arguments

         - argument_default -- The default value for all arguments

         - conflict_handler -- String indicating how to handle conflicts

         - add_help -- Add a -h/-help option

     """

     def __init__(self,

                  prog=None,

                  usage=None,

                  description=None,

                  epilog=None,

                  version=None,

                  parents=[],

                  formatter_class=HelpFormatter,

                  prefix_chars='-',

                  fromfile_prefix_chars=None,

                  argument_default=None,

                  conflict_handler='error',

                  add_help=True):

         if version is not None:

             import warnings

             warnings.warn(

                 """The "version" argument to ArgumentParser is deprecated. """

                 """Please use """

                 """"add_argument(..., action='version', version="N", ...)" """

                 """instead""", DeprecationWarning)

         superinit = super(ArgumentParser, self).__init__

         superinit(description=description,

                   prefix_chars=prefix_chars,

                   argument_default=argument_default,

                   conflict_handler=conflict_handler)

         # default setting for prog

         if prog is None:

             prog = _os.path.basename(_sys.argv[0])

         self.prog = prog

         self.usage = usage

         self.epilog = epilog

         self.version = version

         self.formatter_class = formatter_class

         self.fromfile_prefix_chars = fromfile_prefix_chars

         self.add_help = add_help

         add_group = self.add_argument_group

         self._positionals = add_group(_('positional arguments'))

         self._optionals = add_group(_('optional arguments'))

         self._subparsers = None

         # register types

         def identity(string):

             return string

         self.register('type', None, identity)

         # add help and version arguments if necessary

         # (using explicit default to override global argument_default)

         default_prefix = '-' if '-' in prefix_chars else prefix_chars[0]

         if self.add_help:

             self.add_argument(

                 default_prefix+'h', default_prefix*2+'help',

                 action='help', default=SUPPRESS,

                 help=_('show this help message and exit'))

         if self.version:

             self.add_argument(

                 default_prefix+'v', default_prefix*2+'version',

                 action='version', default=SUPPRESS,

                 version=self.version,

                 help=_("show program's version number and exit"))

         # add parent arguments and defaults

         for parent in parents:

             self._add_container_actions(parent)

             try:

                 defaults = parent._defaults

             except AttributeError:

                 pass

             else:

                 self._defaults.update(defaults)

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

     # Pretty __repr__ methods

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

     def _get_kwargs(self):

         names = [

             'prog',

             'usage',

             'description',

             'version',

             'formatter_class',

             'conflict_handler',

             'add_help',

         ]

         return [(name, getattr(self, name)) for name in names]

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

     # Optional/Positional adding methods

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

     def add_subparsers(self, **kwargs):

         if self._subparsers is not None:

             self.error(_('cannot have multiple subparser arguments'))

         # add the parser class to the arguments if it's not present

         kwargs.setdefault('parser_class', type(self))

         if 'title' in kwargs or 'description' in kwargs:

             title = _(kwargs.pop('title', 'subcommands'))

             description = _(kwargs.pop('description', None))

             self._subparsers = self.add_argument_group(title, description)

         else:

             self._subparsers = self._positionals

         # prog defaults to the usage message of this parser, skipping

         # optional arguments and with no "usage:" prefix

         if kwargs.get('prog') is None:

             formatter = self._get_formatter()

             positionals = self._get_positional_actions()

             groups = self._mutually_exclusive_groups

             formatter.add_usage(self.usage, positionals, groups, '')

             kwargs['prog'] = formatter.format_help().strip()

         # create the parsers action and add it to the positionals list

         parsers_class = self._pop_action_class(kwargs, 'parsers')

         action = parsers_class(option_strings=[], **kwargs)

         self._subparsers._add_action(action)

         # return the created parsers action

         return action

     def _add_action(self, action):

         if action.option_strings:

             self._optionals._add_action(action)

         else:

             self._positionals._add_action(action)

         return action

     def _get_optional_actions(self):

         return [action

                 for action in self._actions

                 if action.option_strings]

     def _get_positional_actions(self):

         return [action

                 for action in self._actions

                 if not action.option_strings]

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

     # Command line argument parsing methods

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

     def parse_args(self, args=None, namespace=None):

         args, argv = self.parse_known_args(args, namespace)

         if argv:

             msg = _('unrecognized arguments: %s')

             self.error(msg % ' '.join(argv))

         return args

     def parse_known_args(self, args=None, namespace=None):

         # args default to the system args

         if args is None:

             args = _sys.argv[1:]

         # default Namespace built from parser defaults

         if namespace is None:

             namespace = Namespace()

         # add any action defaults that aren't present

         for action in self._actions:

             if action.dest is not SUPPRESS:

                 if not hasattr(namespace, action.dest):

                     if action.default is not SUPPRESS:

                         default = action.default

                         if isinstance(action.default, str):

                             default = self._get_value(action, default)

                         setattr(namespace, action.dest, default)

         # add any parser defaults that aren't present

         for dest in self._defaults:

             if not hasattr(namespace, dest):

                 setattr(namespace, dest, self._defaults[dest])

         # parse the arguments and exit if there are any errors

         try:

             return self._parse_known_args(args, namespace)

         except ArgumentError:

             err = _sys.exc_info()[1]

             self.error(str(err))

     def _parse_known_args(self, arg_strings, namespace):

         # replace arg strings that are file references

         if self.fromfile_prefix_chars is not None:

             arg_strings = self._read_args_from_files(arg_strings)

         # map all mutually exclusive arguments to the other arguments

         # they can't occur with

         action_conflicts = {}

         for mutex_group in self._mutually_exclusive_groups:

             group_actions = mutex_group._group_actions

             for i, mutex_action in enumerate(mutex_group._group_actions):

                 conflicts = action_conflicts.setdefault(mutex_action, [])

                 conflicts.extend(group_actions[:i])

                 conflicts.extend(group_actions[i + 1:])

         # find all option indices, and determine the arg_string_pattern

         # which has an 'O' if there is an option at an index,

         # an 'A' if there is an argument, or a '-' if there is a '--'

         option_string_indices = {}

         arg_string_pattern_parts = []

         arg_strings_iter = iter(arg_strings)

         for i, arg_string in enumerate(arg_strings_iter):

             # all args after -- are non-options

             if arg_string == '--':

                 arg_string_pattern_parts.append('-')

                 for arg_string in arg_strings_iter:

                     arg_string_pattern_parts.append('A')

             # otherwise, add the arg to the arg strings

             # and note the index if it was an option

             else:

                 option_tuple = self._parse_optional(arg_string)

                 if option_tuple is None:

                     pattern = 'A'

                 else:

                     option_string_indices[i] = option_tuple

                     pattern = 'O'

                 arg_string_pattern_parts.append(pattern)

         # join the pieces together to form the pattern

         arg_strings_pattern = ''.join(arg_string_pattern_parts)

         # converts arg strings to the appropriate and then takes the action

         seen_actions = set()

         seen_non_default_actions = set()

         def take_action(action, argument_strings, option_string=None):

             seen_actions.add(action)

             argument_values = self._get_values(action, argument_strings)

             # error if this argument is not allowed with other previously

             # seen arguments, assuming that actions that use the default

             # value don't really count as "present"

             if argument_values is not action.default:

                 seen_non_default_actions.add(action)

                 for conflict_action in action_conflicts.get(action, []):

                     if conflict_action in seen_non_default_actions:

                         msg = _('not allowed with argument %s')

                         action_name = _get_action_name(conflict_action)

                         raise ArgumentError(action, msg % action_name)

             # take the action if we didn't receive a SUPPRESS value

             # (e.g. from a default)

             if argument_values is not SUPPRESS:

                 action(self, namespace, argument_values, option_string)

         # function to convert arg_strings into an optional action

         def consume_optional(start_index):

             # get the optional identified at this index

             option_tuple = option_string_indices[start_index]

             action, option_string, explicit_arg = option_tuple

             # identify additional optionals in the same arg string

             # (e.g. -xyz is the same as -x -y -z if no args are required)

             match_argument = self._match_argument

             action_tuples = []

             while True:

                 # if we found no optional action, skip it

                 if action is None:

                     extras.append(arg_strings[start_index])

                     return start_index + 1

                 # if there is an explicit argument, try to match the

                 # optional's string arguments to only this

                 if explicit_arg is not None:

                     arg_count = match_argument(action, 'A')

                     # if the action is a single-dash option and takes no

                     # arguments, try to parse more single-dash options out

                     # of the tail of the option string

                     chars = self.prefix_chars

                     if arg_count == 0 and option_string[1] not in chars:

                         action_tuples.append((action, [], option_string))

                         for char in self.prefix_chars:

                             option_string = char + explicit_arg[0]

                             explicit_arg = explicit_arg[1:] or None

                             optionals_map = self._option_string_actions

                             if option_string in optionals_map:

                                 action = optionals_map[option_string]

                                 break

                         else:

                             msg = _('ignored explicit argument %r')

                             raise ArgumentError(action, msg % explicit_arg)

                     # if the action expect exactly one argument, we've

                     # successfully matched the option; exit the loop

                     elif arg_count == 1:

                         stop = start_index + 1

                         args = [explicit_arg]

                         action_tuples.append((action, args, option_string))

                         break

                     # error if a double-dash option did not use the

                     # explicit argument

                     else:

                         msg = _('ignored explicit argument %r')

                         raise ArgumentError(action, msg % explicit_arg)

                 # if there is no explicit argument, try to match the

                 # optional's string arguments with the following strings

                 # if successful, exit the loop

                 else:

                     start = start_index + 1

                     selected_patterns = arg_strings_pattern[start:]

                     arg_count = match_argument(action, selected_patterns)

                     stop = start + arg_count

                     args = arg_strings[start:stop]

                     action_tuples.append((action, args, option_string))

                     break

             # add the Optional to the list and return the index at which

             # the Optional's string args stopped

             assert action_tuples

             for action, args, option_string in action_tuples:

                 take_action(action, args, option_string)

             return stop

         # the list of Positionals left to be parsed; this is modified

         # by consume_positionals()

         positionals = self._get_positional_actions()

         # function to convert arg_strings into positional actions

         def consume_positionals(start_index):

             # match as many Positionals as possible

             match_partial = self._match_arguments_partial

             selected_pattern = arg_strings_pattern[start_index:]

             arg_counts = match_partial(positionals, selected_pattern)

             # slice off the appropriate arg strings for each Positional

             # and add the Positional and its args to the list

             for action, arg_count in zip(positionals, arg_counts):

                 args = arg_strings[start_index: start_index + arg_count]

                 start_index += arg_count

                 take_action(action, args)

             # slice off the Positionals that we just parsed and return the

             # index at which the Positionals' string args stopped

             positionals[:] = positionals[len(arg_counts):]

             return start_index

         # consume Positionals and Optionals alternately, until we have

         # passed the last option string

         extras = []

         start_index = 0

         if option_string_indices:

             max_option_string_index = max(option_string_indices)

         else:

             max_option_string_index = -1

         while start_index <= max_option_string_index:

             # consume any Positionals preceding the next option

             next_option_string_index = min([

                 index

                 for index in option_string_indices

                 if index >= start_index])

             if start_index != next_option_string_index:

                 positionals_end_index = consume_positionals(start_index)

                 # only try to parse the next optional if we didn't consume

                 # the option string during the positionals parsing

                 if positionals_end_index > start_index:

                     start_index = positionals_end_index

                     continue

                 else:

                     start_index = positionals_end_index

             # if we consumed all the positionals we could and we're not

             # at the index of an option string, there were extra arguments

             if start_index not in option_string_indices:

                 strings = arg_strings[start_index:next_option_string_index]

                 extras.extend(strings)

                 start_index = next_option_string_index

             # consume the next optional and any arguments for it

             start_index = consume_optional(start_index)

         # consume any positionals following the last Optional

         stop_index = consume_positionals(start_index)

         # if we didn't consume all the argument strings, there were extras

         extras.extend(arg_strings[stop_index:])

         # if we didn't use all the Positional objects, there were too few

         # arg strings supplied.

         if positionals:

             self.error(_('too few arguments'))

         # make sure all required actions were present

         for action in self._actions:

             if action.required:

                 if action not in seen_actions:

                     name = _get_action_name(action)

                     self.error(_('argument %s is required') % name)

         # make sure all required groups had one option present

         for group in self._mutually_exclusive_groups:

             if group.required:

                 for action in group._group_actions:

                     if action in seen_non_default_actions:

                         break

                 # if no actions were used, report the error

                 else:

                     names = [_get_action_name(action)

                              for action in group._group_actions

                              if action.help is not SUPPRESS]

                     msg = _('one of the arguments %s is required')

                     self.error(msg % ' '.join(names))

         # return the updated namespace and the extra arguments

         return namespace, extras

     def _read_args_from_files(self, arg_strings):

         # expand arguments referencing files

         new_arg_strings = []

         for arg_string in arg_strings:

             # for regular arguments, just add them back into the list

             if arg_string[0] not in self.fromfile_prefix_chars:

                 new_arg_strings.append(arg_string)

             # replace arguments referencing files with the file content

             else:

                 try:

                     args_file = open(arg_string[1:])

                     try:

                         arg_strings = []

                         for arg_line in args_file.read().splitlines():

                             for arg in self.convert_arg_line_to_args(arg_line):

                                 arg_strings.append(arg)

                         arg_strings = self._read_args_from_files(arg_strings)

                         new_arg_strings.extend(arg_strings)

                     finally:

                         args_file.close()

                 except IOError:

                     err = _sys.exc_info()[1]

                     self.error(str(err))

         # return the modified argument list

         return new_arg_strings

     def convert_arg_line_to_args(self, arg_line):

         return [arg_line]

     def _match_argument(self, action, arg_strings_pattern):

         # match the pattern for this action to the arg strings

         nargs_pattern = self._get_nargs_pattern(action)

         match = _re.match(nargs_pattern, arg_strings_pattern)

         # raise an exception if we weren't able to find a match

         if match is None:

             nargs_errors = {

                 None: _('expected one argument'),

                 OPTIONAL: _('expected at most one argument'),

                 ONE_OR_MORE: _('expected at least one argument'),

             }

             default = _('expected %s argument(s)') % action.nargs

             msg = nargs_errors.get(action.nargs, default)

             raise ArgumentError(action, msg)

         # return the number of arguments matched

         return len(match.group(1))

     def _match_arguments_partial(self, actions, arg_strings_pattern):

         # progressively shorten the actions list by slicing off the

         # final actions until we find a match

         result = []

         for i in range(len(actions), 0, -1):

             actions_slice = actions[:i]

             pattern = ''.join([self._get_nargs_pattern(action)

                                for action in actions_slice])

             match = _re.match(pattern, arg_strings_pattern)

             if match is not None:

                 result.extend([len(string) for string in match.groups()])

                 break

         # return the list of arg string counts

         return result

     def _parse_optional(self, arg_string):

         # if it's an empty string, it was meant to be a positional

         if not arg_string:

             return None

         # if it doesn't start with a prefix, it was meant to be positional

         if not arg_string[0] in self.prefix_chars:

             return None

         # if the option string is present in the parser, return the action

         if arg_string in self._option_string_actions:

             action = self._option_string_actions[arg_string]

             return action, arg_string, None

         # if it's just a single character, it was meant to be positional

         if len(arg_string) == 1:

             return None

         # if the option string before the "=" is present, return the action

         if '=' in arg_string:

             option_string, explicit_arg = arg_string.split('=', 1)

             if option_string in self._option_string_actions:

                 action = self._option_string_actions[option_string]

                 return action, option_string, explicit_arg

         # search through all possible prefixes of the option string

         # and all actions in the parser for possible interpretations

         option_tuples = self._get_option_tuples(arg_string)

         # if multiple actions match, the option string was ambiguous

         if len(option_tuples) > 1:

             options = ', '.join([option_string

                 for action, option_string, explicit_arg in option_tuples])

             tup = arg_string, options

             self.error(_('ambiguous option: %s could match %s') % tup)

         # if exactly one action matched, this segmentation is good,

         # so return the parsed action

         elif len(option_tuples) == 1:

             option_tuple, = option_tuples

             return option_tuple

         # if it was not found as an option, but it looks like a negative

         # number, it was meant to be positional

         # unless there are negative-number-like options

         if self._negative_number_matcher.match(arg_string):

             if not self._has_negative_number_optionals:

                 return None

         # if it contains a space, it was meant to be a positional

         if ' ' in arg_string:

             return None

         # it was meant to be an optional but there is no such option

         # in this parser (though it might be a valid option in a subparser)

         return None, arg_string, None

     def _get_option_tuples(self, option_string):

         result = []

         # option strings starting with two prefix characters are only

         # split at the '='

         chars = self.prefix_chars

         if option_string[0] in chars and option_string[1] in chars:

             if '=' in option_string:

                 option_prefix, explicit_arg = option_string.split('=', 1)

             else:

                 option_prefix = option_string

                 explicit_arg = None

             for option_string in self._option_string_actions:

                 if option_string.startswith(option_prefix):

                     action = self._option_string_actions[option_string]

                     tup = action, option_string, explicit_arg

                     result.append(tup)

         # single character options can be concatenated with their arguments

         # but multiple character options always have to have their argument

         # separate

         elif option_string[0] in chars and option_string[1] not in chars:

             option_prefix = option_string

             explicit_arg = None

             short_option_prefix = option_string[:2]

             short_explicit_arg = option_string[2:]

             for option_string in self._option_string_actions:

                 if option_string == short_option_prefix:

                     action = self._option_string_actions[option_string]

                     tup = action, option_string, short_explicit_arg

                     result.append(tup)

                 elif option_string.startswith(option_prefix):

                     action = self._option_string_actions[option_string]

                     tup = action, option_string, explicit_arg

                     result.append(tup)

         # shouldn't ever get here

         else:

             self.error(_('unexpected option string: %s') % option_string)

         # return the collected option tuples

         return result

     def _get_nargs_pattern(self, action):

         # in all examples below, we have to allow for '--' args

         # which are represented as '-' in the pattern

         nargs = action.nargs

         # the default (None) is assumed to be a single argument

         if nargs is None:

             nargs_pattern = '(-*A-*)'

         # allow zero or one arguments

         elif nargs == OPTIONAL:

             nargs_pattern = '(-*A?-*)'

         # allow zero or more arguments

         elif nargs == ZERO_OR_MORE:

             nargs_pattern = '(-*[A-]*)'

         # allow one or more arguments

         elif nargs == ONE_OR_MORE:

             nargs_pattern = '(-*A[A-]*)'

         # allow any number of options or arguments

         elif nargs == REMAINDER:

             nargs_pattern = '([-AO]*)'

         # allow one argument followed by any number of options or arguments

         elif nargs == PARSER:

             nargs_pattern = '(-*A[-AO]*)'

         # all others should be integers

         else:

             nargs_pattern = '(-*%s-*)' % '-*'.join('A' * nargs)

         # if this is an optional action, -- is not allowed

         if action.option_strings:

             nargs_pattern = nargs_pattern.replace('-*', '')

             nargs_pattern = nargs_pattern.replace('-', '')

         # return the pattern

         return nargs_pattern

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

     # Value conversion methods

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

     def _get_values(self, action, arg_strings):

         # for everything but PARSER args, strip out '--'

         if action.nargs not in [PARSER, REMAINDER]:

             arg_strings = [s for s in arg_strings if s != '--']

         # optional argument produces a default when not present

         if not arg_strings and action.nargs == OPTIONAL:

             if action.option_strings:

                 value = action.const

             else:

                 value = action.default

             if isinstance(value, str):

                 value = self._get_value(action, value)

                 self._check_value(action, value)

         # when nargs='*' on a positional, if there were no command-line

         # args, use the default if it is anything other than None

         elif (not arg_strings and action.nargs == ZERO_OR_MORE and

               not action.option_strings):

             if action.default is not None:

                 value = action.default

             else:

                 value = arg_strings

             self._check_value(action, value)

         # single argument or optional argument produces a single value

         elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:

             arg_string, = arg_strings

             value = self._get_value(action, arg_string)

             self._check_value(action, value)

         # REMAINDER arguments convert all values, checking none

         elif action.nargs == REMAINDER:

             value = [self._get_value(action, v) for v in arg_strings]

         # PARSER arguments convert all values, but check only the first

         elif action.nargs == PARSER:

             value = [self._get_value(action, v) for v in arg_strings]

             self._check_value(action, value[0])

         # all other types of nargs produce a list

         else:

             value = [self._get_value(action, v) for v in arg_strings]

             for v in value:

                 self._check_value(action, v)

         # return the converted value

         return value

     def _get_value(self, action, arg_string):

         type_func = self._registry_get('type', action.type, action.type)

         if not _callable(type_func):

             msg = _('%r is not callable')

             raise ArgumentError(action, msg % type_func)

         # convert the value to the appropriate type

         try:

             result = type_func(arg_string)

         # ArgumentTypeErrors indicate errors

         except ArgumentTypeError:

             name = getattr(action.type, '__name__', repr(action.type))

             msg = str(_sys.exc_info()[1])

             raise ArgumentError(action, msg)

         # TypeErrors or ValueErrors also indicate errors

         except (TypeError, ValueError):

             name = getattr(action.type, '__name__', repr(action.type))

             msg = _('invalid %s value: %r')

             raise ArgumentError(action, msg % (name, arg_string))

         # return the converted value

         return result

     def _check_value(self, action, value):

         # converted value must be one of the choices (if specified)

         if action.choices is not None and value not in action.choices:

             tup = value, ', '.join(map(repr, action.choices))

             msg = _('invalid choice: %r (choose from %s)') % tup

             raise ArgumentError(action, msg)

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

     # Help-formatting methods

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

     def format_usage(self):

         formatter = self._get_formatter()

         formatter.add_usage(self.usage, self._actions,

                             self._mutually_exclusive_groups)

         return formatter.format_help()

     def format_help(self):

         formatter = self._get_formatter()

         # usage

         formatter.add_usage(self.usage, self._actions,

                             self._mutually_exclusive_groups)

         # description

         formatter.add_text(self.description)

         # positionals, optionals and user-defined groups

         for action_group in self._action_groups:

             formatter.start_section(action_group.title)

             formatter.add_text(action_group.description)

             formatter.add_arguments(action_group._group_actions)

             formatter.end_section()

         # epilog

         formatter.add_text(self.epilog)

         # determine help from format above

         return formatter.format_help()

     def format_version(self):

         import warnings

         warnings.warn(

             'The format_version method is deprecated -- the "version" '

             'argument to ArgumentParser is no longer supported.',

             DeprecationWarning)

         formatter = self._get_formatter()

         formatter.add_text(self.version)

         return formatter.format_help()

     def _get_formatter(self):

         return self.formatter_class(prog=self.prog)

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

     # Help-printing methods

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

     def print_usage(self, file=None):

         if file is None:

             file = _sys.stdout

         self._print_message(self.format_usage(), file)

     def print_help(self, file=None):

         if file is None:

             file = _sys.stdout

         self._print_message(self.format_help(), file)

     def print_version(self, file=None):

         import warnings

         warnings.warn(

             'The print_version method is deprecated -- the "version" '

             'argument to ArgumentParser is no longer supported.',

             DeprecationWarning)

         self._print_message(self.format_version(), file)

     def _print_message(self, message, file=None):

         if message:

             if file is None:

                 file = _sys.stderr

             file.write(message)

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

     # Exiting methods

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

     def exit(self, status=0, message=None):

         if message:

             self._print_message(message, _sys.stderr)

         _sys.exit(status)

     def error(self, message):

         """error(message: string)

         Prints a usage message incorporating the message to stderr and

         exits.

         If you override this in a subclass, it should not return -- it

         should either exit or raise an exception.

         """

         self.print_usage(_sys.stderr)

         self.exit(2, _('%s: error: %s\n') % (self.prog, message))