code: def testRegression(self):
      mags = [1, 4, 1.345, 0.321, -4]
      phases = [0.45, 3.14, 2.543, 6.42, 1]
  
      expected = []
      for i in range(len(mags)):
          expected.append(
              mags[i] * cos(phases[i]) + (mags[i] * sin(phases[i])) * 1j
          )
  
      self.assertAlmostEqualVector(
          PolarToCartesian()(mags, phases), expected, 1e-6
      )
  
imports: from essentia_test import *
  from math import sin, cos
label_desc: Use image node_id 2 for calling the TestPolarToCartesian obj's underlying member method code with example usage: obj.testRegression() without return types