code: def testDC(self):
      # Checks the DC component of the transform
      input = essentia.array(np.ones(2**11))
      # Second output of NSGConstantQ contains the DC information nedeed for the inverse transform.
      DCfilter = self.initNsgconstantq()(input)[1]
      # Integrates the energy. DC filter should contain all the energy of the signal in this case.
      DCenergy = np.sum(DCfilter)
      inputEnergy = np.sum(input)
      self.assertEqual(inputEnergy, DCenergy)
  
file_path: essentia/test/src/unittests/standard/test_nsgconstantq.py
imports: from essentia_test import *
  import numpy
label_desc: Use image node_id 3 for calling the TestNSGConstantQ obj's underlying member method code with example usage: obj.testDC() without return types