class_docstr: Contains session data for a single "user" of an active app
  (that is, a connected browser tab).
  
  Each AppSession has its own ScriptData, root DeltaGenerator, ScriptRunner,
  and widget state.
  
  An AppSession is attached to each thread involved in running its script.
class_docstr_tok: ["Contains","session","data","for","a","single","``","user","''","of","an","active","app","(","that","is",",","a","connected","browser","tab",")",".","Each","AppSession","has","its","own","ScriptData",",","root","DeltaGenerator",",","ScriptRunner",",","and","widget","state",".","An","AppSession","is","attached","to","each","thread","involved","in","running","its","script","."]
docstr: Process a BackMsg.
docstr_tok: ["Process","a","BackMsg","."]
code: def handle_backmsg(self, msg: BackMsg) -> None:
      """Process a BackMsg."""
      try:
          msg_type = msg.WhichOneof("type")
  
          if msg_type == "rerun_script":
              if msg.debug_last_backmsg_id:
                  self._debug_last_backmsg_id = (
                      msg.debug_last_backmsg_id
                  )
  
              self._handle_rerun_script_request(msg.rerun_script)
          elif msg_type == "load_git_info":
              self._handle_git_information_request()
          elif msg_type == "clear_cache":
              self._handle_clear_cache_request()
          elif msg_type == "app_heartbeat":
              self._handle_app_heartbeat_request()
          elif msg_type == "set_run_on_save":
              self._handle_set_run_on_save_request(msg.set_run_on_save)
          elif msg_type == "stop_script":
              self._handle_stop_script_request()
          elif msg_type == "file_urls_request":
              self._handle_file_urls_request(msg.file_urls_request)
          else:
              LOGGER.warning('No handler for "%s"', msg_type)
  
      except Exception as ex:
          LOGGER.error(ex)
          self.handle_backmsg_exception(ex)
  
imports: import asyncio
  import sys
  import uuid
  from enum import Enum
  from typing import TYPE_CHECKING, Callable, Dict, List, Optional, Union
  import streamlit.elements.exception
  from streamlit import config, runtime, source_util
  from streamlit.case_converters import to_snake_case
  from streamlit.logger import get_logger
  from streamlit.proto.BackMsg_pb2 import BackMsg
  from streamlit.proto.ClientState_pb2 import ClientState
  from streamlit.proto.Common_pb2 import FileURLs, FileURLsRequest
  from streamlit.proto.ForwardMsg_pb2 import ForwardMsg
  from streamlit.proto.GitInfo_pb2 import GitInfo
  from streamlit.proto.NewSession_pb2 import Config, CustomThemeConfig, NewSession, UserInfo
  from streamlit.proto.PagesChanged_pb2 import PagesChanged
  from streamlit.runtime import caching, legacy_caching
  from streamlit.runtime.forward_msg_queue import ForwardMsgQueue
  from streamlit.runtime.metrics_util import Installation
  from streamlit.runtime.script_data import ScriptData
  from streamlit.runtime.scriptrunner import RerunData, ScriptRunner, ScriptRunnerEvent
  from streamlit.runtime.scriptrunner.script_cache import ScriptCache
  from streamlit.runtime.secrets import secrets_singleton
  from streamlit.runtime.uploaded_file_manager import UploadedFileManager
  from streamlit.version import STREAMLIT_VERSION_STRING
  from streamlit.watcher import LocalSourcesWatcher
label_desc: Use image node_id 8 for calling the AppSession obj's underlying member method code with example usage: obj.handle_backmsg(msg) without return types