code: def test_properties(self):
      # Test setters/getters for cross class properties.
      # This implicitly tests to_ss() and to_zpk()
  
      # Getters
      s = TransferFunction([1, 0], [1, -1], dt=0.05)
      assert_equal(s.poles, [1])
      assert_equal(s.zeros, [0])
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  from numpy.testing import assert_equal, assert_array_almost_equal, assert_array_equal, assert_allclose, assert_, assert_almost_equal
  from pytest import raises
  from scipy._lib._numpy_compat import suppress_warnings
  from scipy.signal import dlsim, dstep, dimpulse, tf2zpk, lti, dlti, StateSpace, TransferFunction, ZerosPolesGain, dfreqresp, dbode, BadCoefficients
label_desc: Use image node_id 3 for calling the TestTransferFunction obj's underlying member method code with example usage: obj.test_properties() without return types