code: def download_pth_file(output_file: str) -> None:
      if not os.path.exists(output_file):
          cmd = [
              "wget",
              " https://download.pytorch.org/models/resnet18-f37072fd.pth",
          ]
          print("Downloading resnet-18 pth file")
          os.system(" ".join(cmd))
  
imports: import argparse
  import os
  import shutil
label_desc: Use image node_id 1 for calling a global function with example usage: download_pth_file(output_file) without return types