code: def test_freq_range(self, xp, scp):
      # Test that freqresp() finds a reasonable frequency range.
      # 1st order low-pass filter: H(z) = 1 / (z - 0.2),
      # Expected range is from 0.01 to 10.
      system = scp.signal.TransferFunction(1, [1, -0.2], dt=0.1)
      n = 10
      w, H = scp.signal.dfreqresp(system, n=n)
      return w, H
  
imports: from math import sqrt, pi
  from pytest import raises
  import cupy
  from cupy import testing
  import cupyx.scipy.signal
label_desc: Use image node_id 3 for calling the Test_dfreqresp obj's underlying member method code with example usage: obj.test_freq_range(xp, scp) and returns: w,  H