code: def main():
      from argparse import ArgumentParser
  
      parser = ArgumentParser(
          description="A simple command line interface for the gzip module: act like gzip, "
          "but do not delete the input file."
      )
      group = parser.add_mutually_exclusive_group()
      group.add_argument(
          "--fast", action="store_true", help="compress faster"
      )
      group.add_argument(
          "--best", action="store_true", help="compress better"
      )
      group.add_argument(
          "-d",
          "--decompress",
          action="store_true",
          help="act like gunzip instead of gzip",
      )
  
      parser.add_argument(
          "args", nargs="*", default=["-"], metavar="file"
      )
      args = parser.parse_args()
  
      compresslevel = _COMPRESS_LEVEL_TRADEOFF
      if args.fast:
          compresslevel = _COMPRESS_LEVEL_FAST
      elif args.best:
          compresslevel = _COMPRESS_LEVEL_BEST
  
      for arg in args.args:
          if args.decompress:
              if arg == "-":
                  f = GzipFile(
                      filename="", mode="rb", fileobj=sys.stdin.buffer
                  )
                  g = sys.stdout.buffer
              else:
                  if arg[-3:] != ".gz":
                      sys.exit(f"filename doesn't end in .gz: {arg!r}")
                  f = open(arg, "rb")
                  g = builtins.open(arg[:-3], "wb")
          else:
              if arg == "-":
                  f = sys.stdin.buffer
                  g = GzipFile(
                      filename="",
                      mode="wb",
                      fileobj=sys.stdout.buffer,
                      compresslevel=compresslevel,
                  )
              else:
                  f = builtins.open(arg, "rb")
                  g = open(arg + ".gz", "wb")
          while True:
              chunk = f.read(io.DEFAULT_BUFFER_SIZE)
              if not chunk:
                  break
              g.write(chunk)
          if g is not sys.stdout.buffer:
              g.close()
          if f is not sys.stdin.buffer:
              f.close()
  
imports: import struct, sys, time, os
  import zlib
  import builtins
  import io
  import _compression
label_desc: Use image node_id 8 for calling a global function with example usage: main() without return types