class_docstr: Wraps a resolver with a mapping of overrides.
  
  This can be used to make local DNS changes (e.g. for testing)
  without modifying system-wide settings.
  
  The mapping can be in three formats::
  
      {
          # Hostname to host or ip
          "example.com": "127.0.1.1",
  
          # Host+port to host+port
          ("login.example.com", 443): ("localhost", 1443),
  
          # Host+port+address family to host+port
          ("login.example.com", 443, socket.AF_INET6): ("::1", 1443),
      }
  
  .. versionchanged:: 5.0
     Added support for host-port-family triplets.
class_docstr_tok: ["Wraps","a","resolver","with","a","mapping","of","overrides",".","This","can","be","used","to","make","local","DNS","changes","(","e.g",".","for","testing",")","without","modifying","system-wide","settings",".","The","mapping","can","be","in","three","formats",":",":","{","#","Hostname","to","host","or","ip","``","example.com","''",":","``","127.0.1.1","''",",","#","Host+port","to","host+port","(","``","login.example.com","''",",","443",")",":","(","``","localhost","''",",","1443",")",",","#","Host+port+address","family","to","host+port","(","``","login.example.com","''",",","443",",","socket.AF_INET6",")",":","(","``",":",":1","''",",","1443",")",",","}","..","versionchanged",":",":","5.0","Added","support","for","host-port-family","triplets","."]
code: def close(self) -> None:
      self.resolver.close()
  
imports: import asyncio
  import concurrent.futures
  import errno
  import os
  import sys
  import socket
  import ssl
  import stat
  from tornado.concurrent import dummy_executor, run_on_executor
  from tornado.ioloop import IOLoop
  from tornado.util import Configurable, errno_from_exception
  from typing import List, Callable, Any, Type, Dict, Union, Tuple, Awaitable, Optional
label_desc: Use image node_id 2 for calling the OverrideResolver obj's underlying member method code with example usage: obj.close() without return types