class_docstr: Base Class for generating a data sample array
code: def duration(self):
      return self.num_samples / self.samplerate
  
imports: from __future__ import division
  import gi
  from gi.repository import GLib, Gst
  import numpy
  import scipy.signal.waveforms
  import os.path
  import ffmpeg
label_desc: Use image node_id 3 for calling the SampleArray obj's underlying member method code with example usage: obj.duration() and returns: unknown