code: def testRegression(self):
      inputc = [(1, -5), (2, -6), (-3, 7), (-4, 8)]
      inputc = numpy.array([complex(*c) for c in inputc], dtype="c8")
      expected = array([abs(c) for c in inputc])
  
      self.assertAlmostEqualVector(Magnitude()(inputc), expected)
  
imports: from essentia_test import *
  from math import *
label_desc: Use image node_id 3 for calling the TestMagnitude obj's underlying member method code with example usage: obj.testRegression() without return types