text: import numpy as np
  from scipy.io import wavfile
  import matplotlib.pyplot as plt
  
  from stretch import stretch
  
  START_SECONDS = 125
  NUM_SECONDS = 10
  TEST_FILE = '/Users/jachowdhury/Downloads/Tennyson - Old Singles/Tennyson - Old Singles - 01 All Yours.wav'
  STRETCH_AMOUNT = 0.5
  
  fs, x = wavfile.read(TEST_FILE)
  x = (np.transpose(x) / np.max(np.abs(x))).astype(np.float32)
  start_idx = int(START_SECONDS * fs)
  n_samples = int(NUM_SECONDS * fs)
  ref_signal = x[:,start_idx : start_idx + n_samples]
  
  # fs = 44100
  # N = int(NUM_SECONDS * fs)
  # FREQ = 50
  # ref_signal = np.zeros((2, N))
  # for ch in range(2):
  #     ref_signal[ch] = np.sin(2 * np.pi * np.arange(N) * FREQ / fs)
  
  wavfile.write('ref.wav', fs, np.transpose(ref_signal))
  
  stretch_signal = stretch(ref_signal, fs, STRETCH_AMOUNT)
  
  wavfile.write(f'stretch_{STRETCH_AMOUNT}.wav', fs, np.transpose(stretch_signal))
  
  # plt.plot(ref_signal[0])
  # plt.plot(np.sin(2 * np.pi * np.arange(len(stretch_signal[0])) * FREQ / fs))
  # plt.plot(stretch_signal[0])
  # plt.show()
  