code: def testInvalidInput(self):
      # mel bands should fail for a spectrum with less than 2 bins
      self.assertComputeFails(MelBands(), [])
      self.assertComputeFails(MelBands(), [0.5])
  
file_path: essentia/test/src/unittests/spectral/test_melbands.py
imports: from essentia_test import *
  import numpy
label_desc: Use image node_id 6 for calling the TestMelBands obj's underlying member method code with example usage: obj.testInvalidInput() without return types