code: def extend_fbins(X):
      """Extending the number of frequency bins from `n_fft//2+1` back to `n_fft` by
      reversing all bins except DC and Nyquist and append it on top of existing spectrogram
      """
      X_upper = X[:, 1:-1].flip(1)
      X_upper[:, :, :, 1] = -X_upper[
          :, :, :, 1
      ]  # For the imaganinry part, it is an odd function
      return torch.cat((X[:, :, :], X_upper), 1)
  
imports: import sys
  import torch
  from torch.nn.functional import conv1d, fold
  import numpy
  from time import time
  import math
  from scipy.signal import get_window
  from scipy import signal
  from scipy.fftpack import fft
  import warnings
  from nnAudio.librosa_functions import *
label_desc: Use image node_id 5 for calling a global function with example usage: extend_fbins(X) and returns: torch