code: def execute_remote(
      cmd: str,
      ip: str,
      port: Optional[int] = 22,
      username: Optional[str] = "",
  ) -> mp.Process:
      """Execute command line on remote machine via ssh.
  
      Args:
          cmd: User-defined command (udf) to execute on the remote host.
          ip: The ip-address of the host to run the command on.
          port: Port number that the host is listening on.
          username: Optional. If given, this will specify a username to use when issuing commands over SSH.
              Useful when your infra requires you to explicitly specify a username to avoid permission issues.
  
      Returns:
          Process: The Process whose run() is to run the `cmd` on the remote host. Returns when the cmd completes
              on the remote host.
      """
      ip_prefix = ""
      if username:
          ip_prefix += "{username}@".format(username=username)
  
      custom_port = os.getenv("DIST_DGL_TEST_SSH_PORT", "")
      if custom_port:
          port = custom_port
  
      custom_ssh_key = os.getenv("DIST_DGL_TEST_SSH_KEY", "")
      if custom_ssh_key:
          custom_ssh_key = os.path.expanduser(custom_ssh_key)
          custom_ssh_key = "-i " + custom_ssh_key
  
      ssh_setup = os.getenv("DIST_DGL_TEST_SSH_SETUP", "")
      if ssh_setup:
          cmd = ssh_setup + ";" + cmd
      # Construct ssh command that executes `cmd` on the remote host
      ssh_cmd = "ssh -o StrictHostKeyChecking=no {ssh_key} -p {port} {ip_prefix}{ip} '{cmd}'".format(
          ssh_key=custom_ssh_key,
          port=str(port),
          ip_prefix=ip_prefix,
          ip=ip,
          cmd=cmd,
      )
      ctx = mp.get_context("spawn")
      proc = ctx.Process(target=run, args=(ssh_cmd,))
      proc.start()
      return proc
  
imports: import multiprocessing
  import os
  import subprocess
  from typing import Optional
label_desc: Use image node_id 2 for calling a global function with example usage: execute_remote(cmd, ip, port, username) and returns: proc