code: def build_gaussian_pyramid(self, src, level=3):
      s = src.copy()
      pyramid = [s]
      for i in range(level):
          s = cv2.pyrDown(s)
          pyramid.append(s)
      return pyramid
  
imports: import cv2
  import numpy
  import imutils
  import scipy.signal
  import scipy.fftpack
  import time
  import sys
  from webcam import Webcam
  from video import Video
  from face_detection import FaceDetection
  from interface import waitKey, plotXY
label_desc: Use image node_id 2 for calling the VidMag obj's underlying member method code with example usage: obj.build_gaussian_pyramid(src, level) and returns: pyramid