code: def testEmpty(self):
      self.assertComputeFails(PowerMean(), [])
      self.assertComputeFails(PowerMean(power=0), [])
  
file_path: essentia/test/src/unittests/stats/test_powermean.py
imports: from essentia_test import *
label_desc: Use image node_id 1 for calling the TestPowerMean obj's underlying member method code with example usage: obj.testEmpty() without return types