code: def parse_helpfull_output(help_output, regex=FLAG_HELP_RE_PY):
      
      valid_flags = set()
      for _, no_prefix, flag_name in regex.findall(help_output):
          valid_flags.add('--' + flag_name)
          if no_prefix:
              valid_flags.add('--no' + flag_name)
      return valid_flags
docs: Parses the output of --helpfull.
  
      Args:
          help_output: str, the full output of --helpfull.
  
      Returns:
          A set of flags that are valid flags.