code: def testIncorrectFlatSign(self):
      chords = [
          "DB",
          "AB",
          "DB",
          "AB",
          "DB",
          "AB",
      ]  # "B" is not accepted for flat.
      self.assertComputeFails(
          ChordsDescriptors(), chords, "DB", "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 7 for calling the TestChordsDescriptors obj's underlying member method code with example usage: obj.testIncorrectFlatSign() without return types