code: def test_error(self):
      # Raise an error for continuous-time systems
      system = signal.lti([1], [1, 1])
      assert_raises(AttributeError, signal.dbode, system)
  
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 6 for calling the Test_bode obj's underlying member method code with example usage: obj.test_error() without return types