class_docstr: Base Class for generating a data sample array
code: def __add__(self, other):
      if not self.samplerate == other.samplerate:
          raise ValueError("Samplerates mismatch")
  
      sum_ = SampleArray(samplerate=self.samplerate)
      sum_.num_samples = self.num_samples + other.num_samples
      sum_.array = numpy.vstack([self.array, other.array])
      return sum_
  
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 4 for calling the SampleArray obj's underlying member method code with example usage: obj.__add__(other) and returns: sum_