code: def test_list_active_sessions(self):
      session_ids = []
      for _ in range(3):
          session_ids.append(self.connect_session())
  
      assert [
          s.session.id for s in self.session_mgr.list_active_sessions()
      ] == session_ids
  
imports: import unittest
  from unittest.mock import MagicMock, patch
  import pytest
  from streamlit.runtime.script_data import ScriptData
  from streamlit.runtime.session_manager import SessionStorage
  from streamlit.runtime.websocket_session_manager import WebsocketSessionManager
label_desc: Use image node_id 17 for calling the WebsocketSessionManagerTests obj's underlying member method code with example usage: obj.test_list_active_sessions() without return types