code: def test_tracker_as_readable_transcript_handles_empty_tracker():
      tracker = DialogueStateTracker(sender_id="test", slots=[])
      assert tracker_as_readable_transcript(tracker) == ""
  
file_path: rasa/tests/utils/test_llm.py
imports: from rasa.shared.core.domain import Domain
  from rasa.shared.core.events import BotUttered, UserUttered
  from rasa.shared.core.trackers import DialogueStateTracker
  from rasa.utils.llm import sanitize_message_for_prompt, tracker_as_readable_transcript
label_desc: Use image node_id 1 for calling a global function with example usage: test_tracker_as_readable_transcript_handles_empty_tracker() without return types