code: def command_exists(self, cmd):
      if "|" in cmd:
          cmds = cmd.split("|")
      else:
          cmds = [cmd]
      valid = False
      for cmd in cmds:
          result = subprocess.Popen(
              f"type {cmd}", stdout=subprocess.PIPE, shell=True
          )
          valid = valid or result.wait() == 0
  
      if not valid and len(cmds) > 1:
          print(
              f"{WARNING} {self.name} requires one of the following commands '{cmds}', but it does not exist!"
          )
      elif not valid and len(cmds) == 1:
          print(
              f"{WARNING} {self.name} requires the '{cmd}' command, but it does not exist!"
          )
      return valid
  
imports: import os
  import time
  import torch
  import importlib
  from pathlib import Path
  import subprocess
  from abc import ABC, abstractmethod
label_desc: Use image node_id 12 for calling the OpBuilder obj's underlying member method code with example usage: obj.command_exists(cmd) and returns: valid