code: def testCaseSensitivityFlatKey(self):
      # Checks that key is case-insensitive in presence of the flat sign.
      upperCase = "Db"
      lowerCase = "db"
      chords = ["Db", "Ab", "Db", "Ab", "Db", "Ab"]
  
      resultUpper = ChordsDescriptors()(chords, upperCase, "MaJoR")
      resultLower = ChordsDescriptors()(chords, lowerCase, "MaJoR")
  
      self.assertEqualVector(resultUpper[0], resultLower[0])
      self.assertAlmostEqual(
          resultUpper[1], resultLower[1]
      )  # chord rate
      self.assertAlmostEqual(
          resultUpper[2], resultLower[2]
      )  # change rate
      self.assertEqual(resultUpper[3], resultLower[3])  # key
      self.assertEqual(resultUpper[4], resultLower[4])
  
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 5 for calling the TestChordsDescriptors obj's underlying member method code with example usage: obj.testCaseSensitivityFlatKey() without return types