code: def energy(frame):
      """Computes signal energy of frame"""
      return np.sum(frame**2) / np.float64(len(frame))
  
imports: from __future__ import print_function
  import math
  import numpy
  import sys
  from scipy.fftpack import fft
  import matplotlib.pyplot
  from scipy.signal import lfilter
  from scipy.fftpack.realtransforms import dct
  from tqdm import tqdm
label_desc: Use image node_id 3 for calling a global function with example usage: energy(frame) and returns: unknown