How to use the picoscope.ps2000 function in picoscope

def __init__(self):
        PicoScopeBase.__init__(self, ps2000.PS2000(connect=False))

from __future__ import absolute_import
from __future__ import print_function
from __future__ import unicode_literals

import time
from picoscope import ps2000
# from picoscope import ps2000a
import pylab as plt
import numpy as np

if __name__ == "__main__":
    print(__doc__)

    print("Attempting to open Picoscope 2000...")

    ps = ps2000.PS2000()
    # Uncomment this line to use with the 2000a/2000b series
    # ps = ps2000a.PS2000a()

    print("Found the following picoscope:")
    print(ps.getAllUnitInfo())

    waveform_desired_duration = 50E-6
    obs_duration = 3 * waveform_desired_duration
    sampling_interval = obs_duration / 4096

    (actualSamplingInterval, nSamples, maxSamples) = \
        ps.setSamplingInterval(sampling_interval, obs_duration)
    print("Sampling interval = %f ns" % (actualSamplingInterval * 1E9))
    print("Taking  samples = %d" % nSamples)
    print("Maximum samples = %d" % maxSamples)