code: def get_transport(host, username, key):
      
  
      if host == shakedown.master_ip():
          transport = paramiko.Transport(host)
      else:
          transport_master = paramiko.Transport(shakedown.master_ip())
          transport_master = start_transport(transport_master, username, key)
  
          if not transport_master.is_authenticated():
              print("error: unable to authenticate {}@{} with key {}".format(username, shakedown.master_ip(), key))
              return False
  
          try:
              channel = transport_master.open_channel('direct-tcpip', (host, 22), ('127.0.0.1', 0))
          except paramiko.SSHException:
              print("error: unable to connect to {}".format(host))
              return False
  
          transport = paramiko.Transport(channel)
  
      return transport
docs: Create a transport object
  
          :param host: the hostname to connect to
          :type host: str
          :param username: SSH username
          :type username: str
          :param key: key object used for authentication
          :type key: paramiko.RSAKey
  
          :return: a transport object
          :rtype: paramiko.Transport