code: def close(self) -> None:
      self._force_timeout_callback.stop()
      if self._timeout is not None:
          self.io_loop.remove_timeout(self._timeout)
      for curl in self._curls:
          curl.close()
      self._multi.close()
      super().close()
  
      # Set below properties to None to reduce the reference count of current
      # instance, because those properties hold some methods of current
      # instance that will case circular reference.
      self._force_timeout_callback = None  # type: ignore
      self._multi = None
  
imports: import collections
  import functools
  import logging
  import pycurl
  import threading
  import time
  from io import BytesIO
  from tornado import httputil
  from tornado import ioloop
  from tornado.escape import utf8, native_str
  from tornado.httpclient import HTTPRequest, HTTPResponse, HTTPError, AsyncHTTPClient, main
  from tornado.log import app_log
  from typing import Dict, Any, Callable, Union, Optional
  import typing
label_desc: Use image node_id 2 for calling the CurlAsyncHTTPClient obj's underlying member method code with example usage: obj.close() without return types