code: def testUnknownKey(self):
      self.assertComputeFails(
          ChordsDescriptors(), ["C", "C"], "Cb", "major"
      )
  
file_path: essentia/test/src/unittests/tonal/test_chordsdescriptors.py
imports: from essentia_test import *
  from essentia.streaming import ChordsDescriptors
label_desc: Use image node_id 8 for calling the TestChordsDescriptors obj's underlying member method code with example usage: obj.testUnknownKey() without return types