code: def testEmpty(self):
      vibrato, extent = Vibrato()([])
      self.assertEqual(vibrato.size, 0)
      self.assertEqual(extent.size, 0)
  
file_path: essentia/test/src/unittests/tonal/test_vibrato.py
imports: from essentia_test import *
  from numpy import sin, float32, pi, arange, mean, log2, floor, ceil
label_desc: Use image node_id 1 for calling the TestVibrato obj's underlying member method code with example usage: obj.testEmpty() without return types