code: def test_c2d_tf(self, xp, scp):
      sys = scp.signal.lti([0.5, 0.3], [1.0, 0.4])
      sys = sys.to_discrete(0.005)
      return sys.num, sys.den
  
imports: import math
  import cupyx.scipy.signal
  import pytest
  from cupy import testing
label_desc: Use image node_id 2 for calling the TestC2dLti obj's underlying member method code with example usage: obj.test_c2d_tf(xp, scp) and returns: sys,  sys