code: def _load_ssh_auth_pre_yosemite():
      
      for process in psutil.process_iter():
          if process.name() == 'ssh-agent':
              ssh_auth_sock = subprocess.check_output(['launchctl', 'bsexec', str(process.pid), 'launchctl', 'getenv', 'SSH_AUTH_SOCK']).rstrip()
              if ssh_auth_sock:
                  _set_ssh_auth_sock(ssh_auth_sock)
                  break
      else:
          daemon_warnings.warn('ssh', 'No running ssh-agent found linked to SSH_AUTH_SOCK')
docs: For OS X versions before Yosemite, many launchd processes run simultaneously under
      different users and different permission models. The simpler `asuser` trick we use
      in Yosemite doesn't work, since it gets routed to the wrong launchd. We instead need
      to find the running ssh-agent process and use its PID to navigate ourselves
      to the correct launchd.