How to use the torchaudio.sox_effects.SoxEffectsChain function in torchaudio

def test_biquad_delay(self):
        si, _ = torchaudio.info(self.test_filepath)
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("biquad", ["0.25136437", "0.50272873", "0.25136437",
                                            "1.0", "-0.17123075", "0.17668821"])
        E.append_effect_to_chain("delay", ["15000s"])
        x, _ = E.sox_build_flow_effects()
        # check if effect worked
        self.assertTrue(x.size(1) == (si.length / si.channels) + 15000)

def test_invalid_effect_name(self):
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        # there is no effect named "special"
        with self.assertRaises(LookupError):
            E.append_effect_to_chain("special", [""])

def test_gain(self):
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("gain", ["5"])
        x, sr = E.sox_build_flow_effects()
        E.clear_chain()
        self.assertTrue(x.abs().max().item(), 1.)
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("gain", ["-e", "-5"])
        x, sr = E.sox_build_flow_effects()
        E.clear_chain()
        self.assertLess(x.abs().max().item(), 1.)
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("gain", ["-b", "8"])
        x, sr = E.sox_build_flow_effects()
        E.clear_chain()
        self.assertTrue(x.abs().max().item(), 1.)
        E.set_input_file(self.test_filepath)

def test_band_chorus(self):
        si_in, ei_in = torchaudio.info(self.test_filepath)
        ei_in.encoding = torchaudio.get_sox_encoding_t(1)
        E = torchaudio.sox_effects.SoxEffectsChain(out_encinfo=ei_in, out_siginfo=si_in)
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("band", ["-n", "10k", "3.5k"])
        E.append_effect_to_chain("chorus", [.5, .7, 55, 0.4, .25, 2, '-s'])
        E.append_effect_to_chain("rate", [si_in.rate])
        E.append_effect_to_chain("channels", [si_in.channels])
        x, sr = E.sox_build_flow_effects()
        # The chorus effect will make the output file longer than the input
        self.assertEqual(x.size(0), si_in.channels)
        self.assertGreaterEqual(x.size(1) * x.size(0), si_in.length)

def test_rate_channels(self):
        target_rate = 16000
        target_channels = 1
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("rate", [target_rate])
        E.append_effect_to_chain("channels", [target_channels])
        x, sr = E.sox_build_flow_effects()
        # check if effects worked
        self.assertEqual(sr, target_rate)
        self.assertEqual(x.size(0), target_channels)

def test_unimplemented_effect(self):
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        # the sox spectrogram function is not implemented in torchaudio
        with self.assertRaises(NotImplementedError):
            E.append_effect_to_chain("spectrogram", [""])

def __init__(self):
        self.asset_dirpath = os.path.join(self.test_dirpath, "assets")
        sound_files = ["sinewave.wav", "steam-train-whistle-daniel_simon.mp3"]
        self.data = [os.path.join(self.asset_dirpath, fn) for fn in sound_files]
        self.si, self.ei = torchaudio.info(os.path.join(self.asset_dirpath, "sinewave.wav"))
        self.si.precision = 16
        self.E = torchaudio.sox_effects.SoxEffectsChain()
        self.E.append_effect_to_chain("rate", [self.si.rate])  # resample to 16000hz
        self.E.append_effect_to_chain("channels", [self.si.channels])  # mono signal
        self.E.append_effect_to_chain("trim", [0, "16000s"])  # first 16000 samples of audio

def test_lowpass_speed(self):
        speed = .8
        si, _ = torchaudio.info(self.test_filepath)
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(self.test_filepath)
        E.append_effect_to_chain("lowpass", 100)
        E.append_effect_to_chain("speed", speed)
        E.append_effect_to_chain("rate", si.rate)
        x, sr = E.sox_build_flow_effects()
        # check if effects worked
        self.assertEqual(x.size(1), int((si.length / si.channels) / speed))

def read_audio(fp, trim_silence=False):
    if trim_silence:
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(fp)

        E.append_effect_to_chain("silence", [1, 100, 1])
        E.append_effect_to_chain("reverse")
        E.append_effect_to_chain("silence", [1, 100, 1])
        E.append_effect_to_chain("reverse")
    
        sig, sample_rate = E.sox_build_flow_effects()
    else:
        sig, sample_rate = torchaudio.load(fp)
    sig = sig.contiguous()
    return sig, sample_rate

def read_audio(fp, downsample=True, trim_silence=True):
    if downsample or trim_silence:
        E = torchaudio.sox_effects.SoxEffectsChain()
        E.set_input_file(fp)

        if trim_silence:
            E.append_effect_to_chain("silence", [1, 100, 1])
            E.append_effect_to_chain("reverse")
            E.append_effect_to_chain("silence", [1, 100, 1])
            E.append_effect_to_chain("reverse")

        if downsample:
            E.append_effect_to_chain("gain", ["-h"])
            E.append_effect_to_chain("channels", [1])
            E.append_effect_to_chain("rate", [16000])
            E.append_effect_to_chain("gain", ["-rh"])
            E.append_effect_to_chain("dither", ["-s"])
    
        sig, sr = E.sox_build_flow_effects()