code: def process_www_authenticate(v):
      if not v:
          return []
      # TODO: provide proper parsing/handling of this custom format and wider support:
      #   <type> realm=<realm>[, charset="UTF-8"]
      # More notes: https://github.com/datalad/datalad/issues/5846#issuecomment-890221053
      # The most complete solution is from 2018 on https://stackoverflow.com/a/52462292/1265472
      # relying on parsing it using pyparsing.
      supported_type = v.split(" ")[0].lower()
      our_type = {
          "basic": "http_basic_auth",
          "digest": "http_digest_auth",
          # TODO: bearer_token_anon ?
      }.get(supported_type)
      return [our_type] if our_type else []
  
imports: import re
  import requests
  import requests.auth
  from requests.utils import parse_dict_header
  import io
  from time import sleep
  from ..None import __version__
  from ..utils import ensure_list_from_str, ensure_dict_from_str, ensure_bytes
  from ..dochelpers import borrowkwargs
  from ..ui import ui
  from ..utils import auto_repr
  from ..support.network import get_url_filename
  from ..support.network import get_response_disposition_filename
  from ..support.network import rfc2822_to_epoch
  from ..support.cookies import cookies_db
  from ..support.status import FileStatus
  from ..support.exceptions import AccessDeniedError, AccessFailedError, CapturedException, DownloadError, UnhandledRedirectError
  from .base import Authenticator
  from .base import BaseDownloader, DownloaderSession
  from logging import getLogger
  from ..log import LoggerHelper
label_desc: Use image node_id 1 for calling a global function with example usage: process_www_authenticate(v) and returns: unknown, list