How to use the phonemizer.separator.default_separator function in phonemizer

def test_english():
    backend = EspeakBackend('en-us')
    text = u'hello world\ngoodbye\nthird line\nyet another'
    out = '\n'.join(backend._phonemize_aux(
        text, separator.default_separator, True))
    assert out == u'həloʊ wɜːld\nɡʊdbaɪ\nθɜːd laɪn\njɛt ɐnʌðɚ'

def test_separator():
    backend = SegmentsBackend('cree')
    text = 'achi acho'

    sep = separator.default_separator
    assert backend.phonemize(text, separator=sep) == u'ʌtʃɪ ʌtʃʊ '
    assert backend.phonemize(text, separator=sep, strip=True) == u'ʌtʃɪ ʌtʃʊ'

def test_str():
    separator = Separator(word='w', syllable='s', phone='p')
    assert str(separator) == '(phone: "p", syllable: "s", word: "w")'
    assert str(default_separator) == '(phone: "", syllable: "", word: " ")'

def test_prop():
    # read only attributes
    with pytest.raises(AttributeError):
        default_separator.phone = 'a'

    with pytest.raises(AttributeError):
        default_separator.syllable = 'a'

    with pytest.raises(AttributeError):
        default_separator.word = 'a'

def test_stress():
    backend = EspeakBackend('en-us', with_stress=False)
    assert u'həloʊ wɜːld' == backend._phonemize_aux(
        u'hello world', separator.default_separator, True)[0]

    backend = EspeakBackend('en-us', with_stress=True)
    assert u'həlˈoʊ wˈɜːld' == backend._phonemize_aux(
        u'hello world', separator.default_separator, True)[0]

def phonemize(text, language='en-us', separator=default_separator,
              strip=False, logger=None):
    """Return a phonemized version of `text` with espeak

    As espeak don't support multiline input, we must run a separate
    espeak for each line of the `text`

    """
    assert language in supported_languages()

    # old espeak versions don't support --sep
    version = espeak_version_short()
    if logger:
        logger.debug('espeak version is: {}'.format(version))

    sep = '--sep=_'
    if version == '1.48.03' or int(version.split('.')[1]) <= 47:

help='number of parallel jobs, default is %(default)s.')

    # input/output arguments
    group = parser.add_argument_group('input/output')
    group.add_argument(
        'input', default=sys.stdin, nargs='?', metavar='',
        help='input text file to phonemize, if not specified read from stdin.')

    group.add_argument(
        '-o', '--output', default=sys.stdout, metavar='',
        help='output text file to write, if not specified write to stdout.')

    group = parser.add_argument_group('separators')
    group.add_argument(
        '-p', '--phone-separator', metavar='',
        default=separator.default_separator.phone,
        help='phone separator, default is "%(default)s".')

    group.add_argument(
        '-w', '--word-separator', metavar='',
        default=separator.default_separator.word,
        help='word separator, default is "%(default)s".')

    group.add_argument(
        '-s', '--syllable-separator', metavar='',
        default=separator.default_separator.syllable,
        help='''syllable separator, only valid for festival backend,
        this option has no effect if espeak or segments is used.
        Default is "%(default)s".''')

    group.add_argument(
        '--strip', action='store_true',

def phonemize(text, language='en-us', backend='festival',
              separator=default_separator, strip=False,
              with_stress=False, use_sampa=False,
              language_switch='keep-flags',
              njobs=1, logger=get_logger()):
    """Multilingual text to phonemes converter

    Return a phonemized version of an input `text`, given its
    `language` and a phonemization `backend`.

    Parameters
    ----------
    text (str or list of str): The text to be phonemized. Any empty
       line will be ignored. If `text` is an str, it can be multiline
       (lines being separated by \n). If `text` is a list, each
       element is considered as a separated line. Each line is
       considered as a text utterance.

def phonemize(text, language='en-us', separator=default_separator,
              strip=False, logger=None):
    """Return a phonemized version of `text` with festival

    This function is a wrapper on festival, a text to speech program,
    allowing simple phonemization of some English text. The US
    phoneset we use is the default one in festival, as described at
    http://www.festvox.org/bsv/c4711.html

    Any opening and closing parenthesis in `text` are removed, as they
    interfer with the Scheme expression syntax. Moreover double quotes
    are replaced by simple quotes because double quotes denotes
    utterances boundaries in festival.

    Parsing a ill-formed Scheme expression during post-processing
    (typically with unbalanced parenthesis) raises an IndexError.

'input', default=sys.stdin, nargs='?', metavar='',
        help='input text file to phonemize, if not specified read from stdin.')

    group.add_argument(
        '-o', '--output', default=sys.stdout, metavar='',
        help='output text file to write, if not specified write to stdout.')

    group = parser.add_argument_group('separators')
    group.add_argument(
        '-p', '--phone-separator', metavar='',
        default=separator.default_separator.phone,
        help='phone separator, default is "%(default)s".')

    group.add_argument(
        '-w', '--word-separator', metavar='',
        default=separator.default_separator.word,
        help='word separator, default is "%(default)s".')

    group.add_argument(
        '-s', '--syllable-separator', metavar='',
        default=separator.default_separator.syllable,
        help='''syllable separator, only valid for festival backend,
        this option has no effect if espeak or segments is used.
        Default is "%(default)s".''')

    group.add_argument(
        '--strip', action='store_true',
        help='removes the end separators in phonemized tokens.')

    group = parser.add_argument_group('backends')
    group.add_argument(
        '-b', '--backend', metavar='', default='espeak',