How to use the niscope.VerticalCoupling.AC function in niscope

def test_fetch_binary16_into(session):
    test_voltage = 1.0
    test_record_length = 2000
    test_channels = range(2)
    test_num_channels = 2
    waveform = numpy.ndarray(test_num_channels * test_record_length, dtype=numpy.int16)
    # Initialize with NaN so we can later verify all samples were overwritten by the driver.
    waveform.fill(float('nan'))
    session.configure_vertical(test_voltage, niscope.VerticalCoupling.AC)
    session.configure_horizontal_timing(50000000, test_record_length, 50.0, 1, True)
    with session.initiate():
        waveforms = session.channels[test_channels].fetch_into(waveform=waveform)

    for sample in waveform:
        assert not math.isnan(sample)
    assert len(waveforms) == test_num_channels

    for i in range(len(waveforms)):
        record_wfm = waveforms[i].samples
        assert len(record_wfm) == test_record_length
        for j in range(len(record_wfm)):
            assert record_wfm[j] == waveform[i * test_record_length + j]

def example(resource_name, channels, options, length, voltage):
    with niscope.Session(resource_name=resource_name, options=options) as session:
        session.configure_vertical(range=voltage, coupling=niscope.VerticalCoupling.AC)
        session.configure_horizontal_timing(min_sample_rate=50000000, min_num_pts=length, ref_position=50.0, num_records=1, enforce_realtime=True)
        with session.initiate():
            waveforms = session.channels[channels].fetch(num_samples=length)
        for i in range(len(waveforms)):
            print('Waveform {0} information:'.format(i))
            print(str(waveforms[i]) + '\n\n')

def example(resource_name, channels, options, length, voltage):
    with niscope.Session(resource_name=resource_name, options=options) as session:
        session.configure_vertical(range=voltage, coupling=niscope.VerticalCoupling.AC)
        session.configure_horizontal_timing(min_sample_rate=50000000, min_num_pts=length, ref_position=50.0, num_records=1, enforce_realtime=True)
        waveforms = session.channels[channels].read(num_samples=length)
        for i in range(len(waveforms)):
            print('Waveform {0} information:'.format(i))
            print(str(waveforms[i]) + '\n\n')