code: def test_transferfunction(self, xp, scp):
      numc = xp.array([0.25, 0.25, 0.5])
      denc = xp.array([0.75, 0.75, 1.0])
      dt_requested = 0.5
  
      c2d = scp.signal.cont2discrete
      num, den, dt = c2d((numc, denc), dt_requested, method="zoh")
      return num, den, dt
  
imports: import math
  import cupyx.scipy.signal
  import pytest
  from cupy import testing
label_desc: Use image node_id 8 for calling the TestC2D obj's underlying member method code with example usage: obj.test_transferfunction(xp, scp) and returns: num,  den,  dt