code: def test_mixture(self):
      # Test one mixture
      x_low = pure_tone(16, sr=128)
      x_high = pure_tone(40, sr=128)
      x = x_low + x_high
      y = resample._downsample2(x)
      y_gt = x_low[::2]
      self.assertSimilar(y, y_gt, x, "mixture")
  
imports: import os
  import tempfile
  import uuid
  from pathlib import Path
  import math
  import random
  import unittest
  import resampy
  import torch
  from julius import resample, ResampleFrac
label_desc: Use image node_id 3 for calling the TestDownsample2 obj's underlying member method code with example usage: obj.test_mixture() without return types