class_docstr: Returns ForwardMsgs from our MessageCache
code: def get(self):
      msg_hash = self.get_argument("hash", None)
      if not config.get_option(
          "global.storeCachedForwardMessagesInMemory"
      ):
          # We use rare status code here, to distinguish between normal 404s.
          self.set_status(418)
          self.finish()
          return
      if msg_hash is None:
          # Hash is missing! This is a malformed request.
          _LOGGER.error(
              "HTTP request for cached message is missing the hash attribute."
          )
          self.set_status(404)
          raise tornado.web.Finish()
  
      message = self._cache.get_message(msg_hash)
      if message is None:
          # Message not in our cache.
          _LOGGER.error(
              "HTTP request for cached message could not be fulfilled. "
              "No such message"
          )
          self.set_status(404)
          raise tornado.web.Finish()
  
      _LOGGER.debug("MessageCache HIT")
      msg_str = serialize_forward_msg(message)
      self.set_header("Content-Type", "application/octet-stream")
      self.write(msg_str)
      self.set_status(200)
  
imports: import os
  import tornado.web
  from streamlit import config, file_util
  from streamlit.logger import get_logger
  from streamlit.runtime.runtime_util import serialize_forward_msg
  from streamlit.web.server.server_util import emit_endpoint_deprecation_notice
label_desc: Use image node_id 3 for calling the MessageCacheHandler obj's underlying member method code with example usage: obj.get() without return types