docs: def _policyFileReplaceOrAppend(this_string, policy_data, append_only=False):
      '''
      helper function to take a ADMX policy string for registry.pol file data and
      update existing string or append the string to the data
      '''
      # we are going to clean off the special pre-fixes, so we get only the valuename
      if not policy_data:
          policy_data = b''
      specialValueRegex = salt.utils.stringutils.to_bytes(r'(\*\*Del\.|\*\*DelVals\.){0,1}')
      item_key = None
      item_value_name = None
      data_to_replace = None
      if not append_only:
          item_key = this_string.split(b'\00;')[0].lstrip(b'[')
          item_value_name = re.sub(specialValueRegex,
                                   b'',
                                   this_string.split(b'\00;')[1],
                                   flags=re.IGNORECASE)
          log.debug('item value name is %s', item_value_name)
          data_to_replace = _regexSearchKeyValueCombo(policy_data, item_key, item_value_name)
      if data_to_replace:
          log.debug('replacing %s with %s', data_to_replace, this_string)
          policy_data = policy_data.replace(data_to_replace, this_string)
      else:
          log.debug('appending %s', this_string)
          policy_data = b''.join([policy_data, this_string])
  
      return policy_data