code: def testRegression(self):
      signal = MonoLoader(
          filename=join(
              testdata.audio_dir,
              "generated",
              "doublesize",
              "sin_30_seconds.wav",
          ),
          sampleRate=44100,
      )()
  
      dcOffset = 0.2
      dcsignal = signal + dcOffset
  
      self.assertAlmostEqual(
          numpy.mean(DCRemoval()(dcsignal)[2500:]), 0, 1e-6
      )
  
file_path: essentia/test/src/unittests/filters/test_dcremoval.py
imports: from essentia_test import *
label_desc: Use image node_id 6 for calling the TestDCRemoval obj's underlying member method code with example usage: obj.testRegression() without return types