code: def testRegression(self):
      self.assertAlmostEqual(
          MaxMagFreq()([3.55, -4.11, 0.443, 3.9555, 2]), 3 * 22050 / 4.0
      )
  
file_path: essentia/test/src/unittests/spectral/test_maxmagfreq.py
imports: from essentia_test import *
label_desc: Use image node_id 4 for calling the TestMaxMagFreq obj's underlying member method code with example usage: obj.testRegression() without return types