code: def test_sph_yn(self):
      sy1 = spherical_yn(2, 0.2)
      sy2 = spherical_yn(0, 0.2)
      assert_almost_equal(
          sy1, -377.52483, 5
      )  # previous values in the system
      assert_almost_equal(sy2, -4.9003329, 5)
      sphpy = (spherical_yn(0, 0.2) - 2 * spherical_yn(2, 0.2)) / 3
      sy3 = spherical_yn(1, 0.2, derivative=True)
      # compare correct derivative val. (correct =-system val).
      assert_almost_equal(sy3, sphpy, 4)
  
imports: import numpy
  from numpy.testing import assert_almost_equal, assert_allclose, assert_array_almost_equal, suppress_warnings
  import pytest
  from numpy import sin, cos, sinh, cosh, exp, inf, nan, r_, pi
  from scipy.special import spherical_jn, spherical_yn, spherical_in, spherical_kn
  from scipy.integrate import quad
label_desc: Use image node_id 5 for calling the TestSphericalOld obj's underlying member method code with example usage: obj.test_sph_yn() without return types