code: def test_c2d_tf(self):
      sys = lti([0.5, 0.3], [1.0, 0.4])
      sys = sys.to_discrete(0.005)
  
      # Matlab results
      num_res = np.array([0.5, -0.485149004980066])
      den_res = np.array([1.0, -0.980198673306755])
  
      # Somehow a lot of numerical errors
      assert_allclose(sys.den, den_res, atol=0.02)
      assert_allclose(sys.num, num_res, atol=0.02)
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_almost_equal, assert_allclose, assert_equal
  import warnings
  from scipy.signal import cont2discrete
  from scipy.signal import dlsim, ss2tf, ss2zpk, lsim2, lti
label_desc: Use image node_id 2 for calling the TestC2dLti obj's underlying member method code with example usage: obj.test_c2d_tf() without return types