def METHOD_NAME():
   global textdata
   if len(sys.argv) < 2:
      show_help_and_exit()
   if sys.argv[1] not in ["-v", "-c"]:
      show_help_and_exit()
   if len(sys.argv) > 2:
      with open(sys.argv[2], 'r') as fh:
         blob = fh.read()
   else:
      blob = download_pci_ids_from_github()
   textdata = blob.splitlines()
   dump_initial_comments()
   if sys.argv[1] == '-v':
      generate_vendors()
   elif sys.argv[1] == '-c':
      generate_device_classes()