code: def test_types(self):
      # backward function
      processor = CombFilterbankProcessor(
          feed_backward_comb_filter, [2, 3], [0.5, 0.5]
      )
      self.assertIsInstance(processor, CombFilterbankProcessor)
      self.assertIsInstance(processor, Processor)
      self.assertTrue(
          processor.filter_function == feed_backward_comb_filter
      )
      processor = CombFilterbankProcessor(
          "backward", [2, 3], [0.5, 0.5]
      )
      self.assertTrue(
          processor.filter_function == feed_backward_comb_filter
      )
      # forward function
      processor = CombFilterbankProcessor(
          feed_forward_comb_filter, [2, 3], [0.5, 0.5]
      )
      self.assertTrue(
          processor.filter_function == feed_forward_comb_filter
      )
      processor = CombFilterbankProcessor("forward", [2, 3], [0.5, 0.5])
      self.assertTrue(
          processor.filter_function == feed_forward_comb_filter
      )
  
imports: from __future__ import absolute_import, division, print_function
  import unittest
  from madmom.audio.comb_filters import *
label_desc: Use image node_id 1 for calling the TestCombFilterbankClass obj's underlying member method code with example usage: obj.test_types() without return types