code: def testZero(self):
      inputSize = 2**15
      signalZero = [0] * inputSize
      output = numpy.mean(
          numpy.abs(Chromagram(normalizeType="none")(signalZero))
      )
      self.assertEqual(0, output)
  
file_path: essentia/test/src/unittests/standard/test_chromagram.py
imports: from essentia_test import *
  import math
  import numpy
  import os
label_desc: Use image node_id 3 for calling the TestChromagram obj's underlying member method code with example usage: obj.testZero() without return types