code: def test_imaginary(self):
      # bode() should not fail on a system with pure imaginary poles.
      # The test passes if bode doesn't raise an exception.
      system = signal.TransferFunction([1], [1, 0, 100], dt=0.1)
      signal.dbode(system, n=2)
  
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 5 for calling the Test_bode obj's underlying member method code with example usage: obj.test_imaginary() without return types