code: def close(self, graceful: bool) -> None:
      if self.sock:
          if graceful:
              try:
                  self.sock.send(b"q")
              except Exception:
                  pass
          self.sock.close()
          self.sock = None
  
imports: import logging
  import os
  import selectors
  import signal
  import socket
  import subprocess
  import time
  from typing import Any, Callable, Dict, List, Optional, Tuple, Union
  import determined
label_desc: Use image node_id 3 for calling the PIDClient obj's underlying member method code with example usage: obj.close(graceful) without return types