code: def get_modified_time(self) -> None:
      # We do not track last modified time, but this can be improved to
      # allow caching among files in the MediaFileManager
      return None
  
file_path: streamlit/lib/streamlit/web/server/media_file_handler.py
imports: from typing import Optional
  from urllib.parse import quote
  import tornado.web
  from streamlit.logger import get_logger
  from streamlit.runtime.media_file_storage import MediaFileKind, MediaFileStorageError
  from streamlit.runtime.memory_media_file_storage import MemoryMediaFileStorage, get_extension_for_mimetype
  from streamlit.web.server import allow_cross_origin_requests
label_desc: Use image node_id 6 for calling the MediaFileHandler obj's underlying member method code with example usage: obj.get_modified_time() and returns: None