code: def test_unregister_exist_event_callback_success(self):
      original_event_listeners = (
          jax_src_monitoring.get_event_listeners()
      )
      callback = lambda event: None
      self.assertNotIn(callback, original_event_listeners)
      monitoring.register_event_listener(callback)
      self.assertIn(callback, jax_src_monitoring.get_event_listeners())
      # Verify that original listeners list is not modified by register function.
      self.assertNotEqual(
          original_event_listeners,
          jax_src_monitoring.get_event_listeners(),
      )
  
      jax_src_monitoring._unregister_event_listener_by_callback(
          callback
      )
  
      self.assertEqual(
          original_event_listeners,
          jax_src_monitoring.get_event_listeners(),
      )
  
file_path: jax/tests/monitoring_test.py
imports: from absl.testing import absltest
  from jax import monitoring
  from jax._src import monitoring
label_desc: Use image node_id 9 for calling the MonitoringTest obj's underlying member method code with example usage: obj.test_unregister_exist_event_callback_success() without return types