code: def close(self):
      command = [
          "ssh",
          "-S",
          self.control_sock_path,
          "-O",
          "exit",
          self.host,
      ]
      subprocess.run(
          command, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL
      )
  
file_path: dstack/src/dstack/_internal/core/services/ssh/tunnel.py
imports: import os
  import subprocess
  import tempfile
  from typing import Dict, Optional
  from dstack._internal.core.services.ssh import get_ssh_error
  from dstack._internal.utils.logging import get_logger
  from dstack._internal.utils.path import PathLike
label_desc: Use image node_id 3 for calling the SSHTunnel obj's underlying member method code with example usage: obj.close() without return types