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 document(self) -> Document:
      return self._document
  
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 2 for calling the ServerSession obj's underlying member method code with example usage: obj.document() and returns: self