code: def test_handle_message_error_reply(self):
      def raise_error(msg=None, metadata=None):
          raise Exception("Test")
  
      def assert_error(msg=None, metadata=None):
          self.assertEqual(metadata["msg_type"], "Error")
          self.assertTrue(
              metadata["traceback"].endswith("Exception: Test")
          )
  
      comm = Comm(id="Test", on_msg=raise_error)
      comm.send = assert_error
      comm._handle_msg({})
  
file_path: holoviews/holoviews/tests/plotting/test_comms.py
imports: from pyviz_comms import Comm, JupyterComm
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 4 for calling the TestComm obj's underlying member method code with example usage: obj.test_handle_message_error_reply() without return types