code: def connection_lost(self, exc):
      self.closed = True
      self.fut.set_result(None)
  
imports: import asyncio
  import errno
  import os
  import socket
  import sys
  import tempfile
  import unittest
  from asyncio import base_events
  from asyncio import constants
  from unittest import mock
  from test import support
  from test.support import os_helper
  from test.support import socket_helper
  from test.test_asyncio import utils
label_desc: Use image node_id 4 for calling the MyProto obj's underlying member method code with example usage: obj.connection_lost(exc) without return types