How to use the nlpaug.util.AudioLoader function in nlpaug

def setUpClass(cls):
        env_config_path = os.path.abspath(os.path.join(
            os.path.dirname(__file__), '..', '..', '..', '.env'))
        load_dotenv(env_config_path)
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        cls.sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )
        cls.audio, cls.sampling_rate = AudioLoader.load_audio(cls.sample_wav_file)

def test_audio(self):
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )

        audio, sampling_rate = AudioLoader.load_audio(sample_wav_file)

        flow = naf.Sequential([
            naa.NoiseAug(),
            naa.PitchAug(sampling_rate=sampling_rate, factor=(0.2, 1.5)),
            naa.ShiftAug(sampling_rate=sampling_rate, duration=2),
            naa.SpeedAug(factor=(1.5, 3))
        ])

        augmented_audio = flow.augment(audio)

        self.assertFalse(np.array_equal(audio, augmented_audio))
        self.assertTrue(len(audio), len(augmented_audio))

def setUpClass(cls):
        env_config_path = os.path.abspath(os.path.join(
            os.path.dirname(__file__), '..', '..', '..', '.env'))
        load_dotenv(env_config_path)
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        cls.sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )
        # https://en.wikipedia.org/wiki/Colors_of_noise
        cls.noise_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Pink_noise.ogg'
        )
        cls.audio, cls.sampling_rate = AudioLoader.load_audio(cls.sample_wav_file)
        cls.noise, cls.noise_sampling_rate = AudioLoader.load_audio(cls.noise_wav_file)

def setUpClass(cls):
        env_config_path = os.path.abspath(os.path.join(
            os.path.dirname(__file__), '..', '..', '..', '.env'))
        load_dotenv(env_config_path)
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        cls.sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )
        cls.audio, cls.sampling_rate = AudioLoader.load_audio(cls.sample_wav_file)

def setUpClass(cls):
        env_config_path = os.path.abspath(os.path.join(
            os.path.dirname(__file__), '..', '..', '..', '.env'))
        load_dotenv(env_config_path)
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        cls.sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )
        cls.audio, cls.sampling_rate = AudioLoader.load_audio(cls.sample_wav_file)

def test_substitute(self):
        audio, sampling_rate = AudioLoader.load_audio(self.sample_wav_file)

        aug = naa.ShiftAug(sampling_rate, duration=0.5)
        augmented_audio = aug.augment(audio)

        self.assertFalse(np.array_equal(audio, augmented_audio))
        self.assertTrue(len(audio), len(augmented_audio))

def setUpClass(cls):
        env_config_path = os.path.abspath(os.path.join(
            os.path.dirname(__file__), '..', '..', '..', '.env'))
        load_dotenv(env_config_path)
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        cls.sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )
        cls.audio, cls.sampling_rate = AudioLoader.load_audio(cls.sample_wav_file)

def test_substitute(self):
        time_mask_para = 80

        mel_spectrogram = AudioLoader.load_mel_spectrogram(self.sample_wav_file, n_mels=self.num_of_freq_channel)
        aug = TimeMaskingAug(mask_factor=time_mask_para)

        augmented_mel_spectrogram = aug.augment(mel_spectrogram)

        self.assertEqual(len(mel_spectrogram[:, aug.model.t0]), np.count_nonzero(mel_spectrogram[:, aug.model.t0]))
        self.assertEqual(0, np.count_nonzero(augmented_mel_spectrogram[:, aug.model.t0]))

def test_spectrogram(self):
        # https://freewavesamples.com/yamaha-v50-rock-beat-120-bpm
        sample_wav_file = os.path.join(
            os.environ.get("TEST_DIR"), 'res', 'audio', 'Yamaha-V50-Rock-Beat-120bpm.wav'
        )

        mel_spectrogram = AudioLoader.load_mel_spectrogram(sample_wav_file, n_mels=128)

        flow = naf.Sequential([
            nas.FrequencyMaskingAug(mask_factor=50),
            nas.TimeMaskingAug(mask_factor=20),
            nas.TimeMaskingAug(mask_factor=30)])

        augmented_mel_spectrogram = flow.augment(mel_spectrogram)

        for aug in flow:
            if aug.name == 'FrequencyMasking_Aug':
                self.assertEqual(len(mel_spectrogram[aug.model.f0]), np.count_nonzero(mel_spectrogram[aug.model.f0]))
                self.assertEqual(0, np.count_nonzero(augmented_mel_spectrogram[aug.model.f0]))
            elif aug.name == 'TimeMasking_Aug':
                self.assertEqual(len(mel_spectrogram[:, aug.model.t0]),
                                 np.count_nonzero(mel_spectrogram[:, aug.model.t0]))
                self.assertEqual(0, np.count_nonzero(augmented_mel_spectrogram[:, aug.model.t0]))

def test_multi_thread(self):
        mel_spectrogram = AudioLoader.load_mel_spectrogram(self.sample_wav_file, n_mels=128)
        n = 3
        augs = [
            nas.FrequencyMaskingAug(mask_factor=80),
            nas.TimeMaskingAug(mask_factor=80)
        ]

        for num_thread in [1, 3]:
            for aug in augs:
                augmented_data = aug.augment(mel_spectrogram, n=n, num_thread=num_thread)
                self.assertEqual(len(augmented_data), n)