How to use the phonemizer.backend.EspeakBackend function in phonemizer

def test_punctuation(text, strip, sep):
    if sep == separator.Separator():
        expected = 'ɐ kɑːmə ɐ pɔɪnt' if strip else 'ɐ kɑːmə ɐ pɔɪnt '
    else:
        expected = (
            'ɐ_k ɑː m ə_ɐ_p ɔɪ n t' if strip else 'ɐ _k ɑː m ə _ɐ _p ɔɪ n t _')

    output = EspeakBackend('en-us').phonemize(text, strip=strip, separator=sep)
    assert expected == output

backend = EspeakBackend('fr-fr', language_switch='remove-flags')
    out = backend._phonemize_aux(text, separator.Separator(), True)
    assert out == [
        'ʒɛm lɑ̃ɡlɛ',
        'ʒɛm lə- fʊtbɔːl',
        'fʊtbɔːl',
        'syʁtu lə- ɹiəl madʁid',
        'nytiliz pa ɡuːɡəl']

    backend = EspeakBackend('fr-fr', language_switch='remove-utterance')
    out = backend._phonemize_aux(text, separator.Separator(), True)
    assert out == ['ʒɛm lɑ̃ɡlɛ']

    with pytest.raises(RuntimeError):
        backend = EspeakBackend('fr-fr', language_switch='foo')

def test_phone_separator(text, expected):
    sep = separator.Separator(phone='_')
    backend = EspeakBackend('en-us')
    output = backend.phonemize(text, separator=sep, strip=True)
    assert output == expected

def test_versions(version):
    expected = '1.49.2' if 'NG' in version else '1.48.03'
    version_re = EspeakBackend.espeak_version_re
    assert re.match(version_re, version).group(1) == expected

def test_french():
    backend = EspeakBackend('fr-fr')
    text = u'bonjour le monde'
    sep = separator.Separator(word=';eword ', syllable=None, phone=' ')
    expected = [u'b ɔ̃ ʒ u ʁ ;eword l ə- ;eword m ɔ̃ d ;eword ']
    out = backend._phonemize_aux(text, sep, False)
    assert out == expected

def test_phone_separator_simple():
    text = 'The lion and the tiger ran'
    sep = separator.Separator(phone='_')
    backend = EspeakBackend('en-us')

    output = backend.phonemize(text, separator=sep, strip=True)
    expected = 'ð_ə l_aɪə_n æ_n_d ð_ə t_aɪ_ɡ_ɚ ɹ_æ_n'
    assert expected == output

    output = backend.phonemize(text, separator=sep, strip=False)
    expected = 'ð_ə_ l_aɪə_n_ æ_n_d_ ð_ə_ t_aɪ_ɡ_ɚ_ ɹ_æ_n_ '
    assert expected == output