docs: def fork_exec(args, stdin='', **kwargs):
      """
      Do a fork-exec through the subprocess.Popen abstraction in a way
      that takes a stdin and return stdout.
      """
  
      as_bytes = isinstance(stdin, bytes)
      source = stdin if as_bytes else stdin.encode(locale)
      p = Popen(args, stdin=PIPE, stdout=PIPE, stderr=PIPE, **kwargs)
      stdout, stderr = p.communicate(source)
      if as_bytes:
          return stdout, stderr
      return (stdout.decode(locale), stderr.decode(locale))