code: def test_close_session_on_invalid_session_id(self):
      self.session_mgr.close_session("nonexistent_session")
  
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 20 for calling the WebsocketSessionManagerTests obj's underlying member method code with example usage: obj.test_close_session_on_invalid_session_id() without return types