code: def validate_custom_args(args: str) -> list[str]:
      unpaper_args = shlex.split(args)
      if any(
          ("/" in arg or arg == "." or arg == "..")
          for arg in unpaper_args
      ):
          raise ValueError("No filenames allowed in --unpaper-args")
      return unpaper_args
  
imports: from __future__ import annotations
  import logging
  import os
  import shlex
  import sys
  from collections.abc import Iterator
  from contextlib import contextmanager
  from decimal import Decimal
  from pathlib import Path
  from subprocess import PIPE, STDOUT
  from tempfile import TemporaryDirectory
  from typing import Union
  from packaging.version import Version
  from PIL import Image
  from ocrmypdf.exceptions import MissingDependencyError, SubprocessOutputError
  from ocrmypdf.subprocess import get_version, run
label_desc: Use image node_id 4 for calling a global function with example usage: validate_custom_args(args) and returns: unpaper_args