code: def update_watched_pages(self) -> None:
      old_watched_pages = self._watched_pages
      new_pages_paths: Set[str] = set()
  
      for page_info in get_pages(self._main_script_path).values():
          new_pages_paths.add(page_info["script_path"])
          if page_info["script_path"] not in old_watched_pages:
              self._register_watcher(
                  page_info["script_path"],
                  module_name=None,
              )
  
      for old_page_path in old_watched_pages:
          if old_page_path not in new_pages_paths:
              self._deregister_watcher(old_page_path)
  
      self._watched_pages = new_pages_paths
  
imports: import collections
  import os
  import sys
  import types
  from typing import Callable, Dict, List, Optional, Set
  from streamlit import config, file_util
  from streamlit.folder_black_list import FolderBlackList
  from streamlit.logger import get_logger
  from streamlit.source_util import get_pages
  from streamlit.watcher.path_watcher import NoOpPathWatcher, get_default_path_watcher_class
label_desc: Use image node_id 2 for calling the LocalSourcesWatcher obj's underlying member method code with example usage: obj.update_watched_pages() without return types