class_docstr: Representation of an SSH connection.
      
class_docstr_tok: ["Representation","of","an","SSH","connection","."]
docstr: determine which ssh client executable should be used.
          
code: def ssh_executable(self):
      """determine which ssh client executable should be used."""
      if not self._ssh_executable:
          from datalad import cfg
  
          self._ssh_executable = cfg.obtain("datalad.ssh.executable")
      return self._ssh_executable
  
imports: import fasteners
  import os
  import logging
  from socket import gethostname
  from hashlib import md5
  from subprocess import Popen
  import tempfile
  import threading
  from datalad.utils import quote_cmdlinearg
  from datalad.support.exceptions import CapturedException, CommandError, ConnectionOpenFailedError
  from datalad.support.external_versions import external_versions
  from datalad.utils import auto_repr, Path, ensure_list, on_windows
  from datalad.cmd import NoCapture, StdOutErrCapture, WitlessRunner
  from ..None import cfg
label_desc: Use image node_id 5 for calling the BaseSSHConnection obj's underlying member method code with example usage: obj.ssh_executable() and returns: self