code: def try_passwordless_ssh(server, keyfile, paramiko=None):
      """Attempt to make an ssh connection without a password.
      This is mainly used for requiring password input only once
      when many tunnels may be connected to the same server.
  
      If paramiko is None, the default for the platform is chosen.
      """
      if paramiko is None:
          paramiko = sys.platform == "win32"
      if not paramiko:
          f = _try_passwordless_openssh
      else:
          f = _try_passwordless_paramiko
      return f(server, keyfile)
  
imports: from __future__ import print_function
  import atexit
  import os
  import re
  import signal
  import socket
  import sys
  import warnings
  from getpass import getpass, getuser
  from multiprocessing import Process
  from ..utils.strtypes import b
label_desc: Use image node_id 2 for calling a global function with example usage: try_passwordless_ssh(server, keyfile, paramiko) and returns: f