class_docstr: Hosts an application "instance" (an instantiated Document) for one or more connections.
  
      
class_docstr_tok: ["Hosts","an","application","``","instance","''","(","an","instantiated","Document",")","for","one","or","more","connections","."]
code: def _session_callback_added(self, event: SessionCallback):
      wrapped = self._wrap_session_callback(event.callback)
      self._callbacks.add_session_callback(wrapped)
  
imports: from __future__ import annotations
  import logging
  import inspect
  import time
  from copy import copy
  from functools import wraps
  from typing import TYPE_CHECKING, Any, Awaitable, Callable, TypeVar
  from tornado import locks
  from ..events import ConnectionLost
  from ..util.token import generate_jwt_token
  from .callbacks import DocumentCallbackGroup
label_desc: Use image node_id 22 for calling the ServerSession obj's underlying member method code with example usage: obj._session_callback_added(event) without return types