code: def test_session_start_is_not_serialised(domain: Domain):
      tracker = DialogueStateTracker("default", domain.slots)
      # the retrieved tracker should be empty
      assert len(tracker.events) == 0
  
      # add SlotSet event
      tracker.update(SlotSet("slot", "value"))
  
      # add the two SessionStarted events and a user event
      tracker.update(ActionExecuted(ACTION_SESSION_START_NAME))
      tracker.update(SessionStarted())
      tracker.update(
          UserUttered(
              "say something", intent={INTENT_NAME_KEY: "some_intent"}
          )
      )
      tracker.update(DefinePrevUserUtteredFeaturization(False))
  
      YAMLStoryWriter().dumps(
          Story.from_events(tracker.events, "some-story01").story_steps
      )
  
      expected = f"""version: "{LATEST_TRAINING_DATA_FORMAT_VERSION}"
  stories:
  - story: some-story01
    steps:
    - slot_was_set:
      - slot: value
    - intent: some_intent
  """
  
      actual = YAMLStoryWriter().dumps(
          Story.from_events(tracker.events, "some-story01").story_steps
      )
      assert actual == expected
  
file_path: rasa/tests/shared/core/training_data/test_structures.py
imports: import rasa.core
  from rasa.shared.constants import LATEST_TRAINING_DATA_FORMAT_VERSION
  from rasa.shared.core.constants import ACTION_SESSION_START_NAME
  from rasa.shared.core.domain import Domain
  from rasa.shared.core.events import SessionStarted, SlotSet, UserUttered, ActionExecuted, DefinePrevUserUtteredFeaturization
  from rasa.shared.core.trackers import DialogueStateTracker
  from rasa.shared.core.training_data.story_reader.yaml_story_reader import YAMLStoryReader
  from rasa.shared.core.training_data.story_writer.yaml_story_writer import YAMLStoryWriter
  from rasa.shared.core.training_data.structures import Story
  from rasa.shared.nlu.constants import INTENT_NAME_KEY
label_desc: Use image node_id 1 for calling a global function with example usage: test_session_start_is_not_serialised(domain) without return types