code: def testRegression(self):
      (
          key,
          scale,
          strength,
          firstToSecondRelativeStrength,
      ) = self.runAlg()
      self.assertEqual(key, "C")
      self.assertEqual(scale, "major")
      self.assertAlmostEqual(strength, 0.760322451591, 1e-6)
      self.assertAlmostEqual(
          firstToSecondRelativeStrength, 0.607807099819, 1e-6
      )
  
file_path: essentia/test/src/unittests/tonal/test_key.py
imports: from essentia_test import *
label_desc: Use image node_id 6 for calling the TestKey obj's underlying member method code with example usage: obj.testRegression() without return types