code: def test_constant(self):
      x = th.ones(2048)
      for zeros in [4, 10]:
          for freq in [0.01, 0.1]:
              y = filters.bandpass_filter(
                  x, freq, 1.2 * freq, zeros=zeros
              )
              self.assertLessEqual(y.abs().mean(), 1e-6, (zeros, freq))
  
imports: import random
  import unittest
  import torch
  from julius.core import pure_tone
  from julius import filters
label_desc: Use image node_id 5 for calling the TestBandPassFilters obj's underlying member method code with example usage: obj.test_constant() without return types